v0.2.22

CHANGELOG.md

@@ -1,5 +1,20 @@
 # RustBox changelog
 
+### 0.2.22
+
+- Added message snooze. A new `snoozed_messages` table (migration `V052`) records a wake time for a message; snoozing it (via the new "Snooze…" context-menu entry or the `b` shortcut while a message is open) hides it client-side from its folder's current view until that time, using `GET /folders/{name}/snoozed-uids` to know which UIDs are currently asleep. `POST /messages/{folder}/{uid}/snooze` and `DELETE /messages/{folder}/{uid}/snooze` set/clear a snooze; `GET /messages/snoozed` lists everything currently sleeping, shown in the new "View snoozed messages…" dialog (`Shift+B`). This is purely a local cache: it has no IMAP side effects and does not change server-side folder pagination/count queries.
+- Added an "Undo Send" window. New `undo_send_window_secs` config setting (default `8`, max `120`; `0` restores the previous immediate-send behavior). When enabled, submitting a message stages it in memory instead of sending it right away; the composer shows a toast with an "Undo" action and countdown, and the message is only dispatched to SMTP once the window elapses without being cancelled. `GET /messages/send/{pending_send_id}` polls status (`pending`/`dispatching`/`sent`/`cancelled`/`failed`); `DELETE /messages/send/{pending_send_id}` cancels a still-pending send. Nothing is persisted, so a server restart during the window drops the staged send the same way an in-flight SMTP connection would be lost.
+- Bumped the application/source release to 0.2.22.
+
+### 0.2.21
+
+- Added configurable login brute-force protection under `[login_rate_limit]` (env: `LOGIN_RATE_LIMIT__*`): the per-IP token bucket on `POST /api/auth/login` is now driven by `ip_burst`/`ip_replenish_secs` instead of hard-coded values, plus failed-attempt lockouts per mailbox (`account_max_failures`, any IP) and per client IP (`ip_max_failures`, password spraying) with exponential back-off (`lockout_secs` → `max_lockout_secs`). Locked attempts return `429` with `Retry-After` before any IMAP connection is opened.
+- The public `GET /api/auth/policy` no longer consumes the per-IP login budget.
+- Added `cookie_secure = "auto" | "always" | "never"` (env: `COOKIE_SECURE`). The default `auto` sets the `Secure` cookie attribute only when the browser actually reached RustBox over HTTPS (trusted-proxy `X-Forwarded-Proto`/`Forwarded`/`X-Forwarded-Ssl`, otherwise the `Origin`/`Referer` scheme). Previously `Secure` depended on `environment != "development"`, which broke logins on plain-HTTP production installs and left cookies without `Secure` in development behind HTTPS.
+- Added memory guards for messages with attachments. An attachment set that cannot fit `max_message_size_mb` once base64-encoded is now rejected with `413` from the stored sizes before any blob is read when sending, saving an IMAP draft snapshot or attaching a message, and while an upload is still streaming (previously the limit was only checked after the whole MIME message had been built in RAM). New `max_concurrent_message_builds` (default 4) and `message_build_wait_secs` (default 30) limit how many requests hold attachment data in memory at once; extra requests wait and then receive `503`. Environment: `MAX_CONCURRENT_MESSAGE_BUILDS`, `MESSAGE_BUILD_WAIT_SECS`.
+- Gmail-style message row opening: outside selection mode, Ctrl/Cmd+click a message opens it in a new browser tab, and Shift+click opens it in a small popup window; both deep-link to the exact message so the new tab/window loads it directly. Plain click and existing selection-mode shift/ctrl range/toggle behavior are unchanged.
+- Bumped the application/source release to 0.2.21.
+
 ### 0.2.20
 
 - Fixed interrupted initial-backfill recovery so legacy missing-date repair does not run against an invalidated or incomplete folder cache.

Cargo.lock

@@ -3506,7 +3506,7 @@ dependencies = [
 
 [[package]]
 name = "rustbox"
-version = "0.2.20"
+version = "0.2.22"
 dependencies = [
  "aes-gcm",
  "async-imap",

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rustbox"
-version = "0.2.20"
+version = "0.2.22"
 edition = "2024"
 rust-version = "1.99.1"
 default-run = "rustbox"

NOTICE.md

@@ -1,6 +1,6 @@
 # RustBox attribution / notice
 
-RustBox 0.2.20 is derived from the Oxi webmail project:
+RustBox 0.2.22 is derived from the Oxi webmail project:
 
 - Upstream: `c0h1b4/oxi`
 - Base snapshot: `7f1507c486b78cf33e54beb701dd460d3bd2bd5d`

README.md

@@ -1,4 +1,4 @@
-# RustBox 0.2.20
+# RustBox 0.2.22
 
 RustBox is a webmail derived from `c0h1b4/oxi`. The consumed Oxi revision is recorded in `UPSTREAM_BASE`.
 
@@ -59,6 +59,10 @@ Administrator-only deep runtime diagnostics can be enabled separately under `[di
 
 Mail endpoints are configured by the administrator, not on the login screen. Users enter only email and password.
 
+Login brute-force protection is on by default and configured in the `[login_rate_limit]` section (or `LOGIN_RATE_LIMIT__*` environment variables): a per-IP token bucket on the login endpoint plus failed-attempt lockouts per mailbox and per client IP with exponential back-off. Locked attempts are answered with `429` and `Retry-After` without contacting the IMAP server. Counters are in memory per node. See `config.example.toml` for every option.
+
+Session cookies get the `Secure` attribute according to `cookie_secure` (default `auto`): only when the browser reached RustBox over HTTPS, detected from a trusted proxy's `X-Forwarded-Proto`/`Forwarded`/`X-Forwarded-Ssl` header or the browser's `Origin`/`Referer`. Plain-HTTP installations keep working; set `cookie_secure = "always"` behind an HTTPS proxy that does not forward the scheme.
+
 Edit `config.dev.toml` before the first run:
 
 ```toml
@@ -77,6 +81,15 @@ tls_enabled = true
 max_attachment_size_mb = 10
 # Hard limit for the complete rendered RFC822/MIME message submitted to the MTA.
 max_message_size_mb = 50
+# Memory guard for messages with attachments. Sending a message or saving an IMAP
+# draft snapshot loads every attachment into RAM and the MIME builder keeps several
+# copies (about 3-4x the message size). Attachment sets that cannot fit
+# max_message_size_mb are rejected with 413 before any file is read, and at most
+# max_concurrent_message_builds requests may hold attachments in memory at once;
+# the others wait up to message_build_wait_secs and then get 503.
+# Rough peak RAM = max_concurrent_message_builds x 4 x max_message_size_mb.
+max_concurrent_message_builds = 4
+message_build_wait_secs = 30
 
 # Optional features exposed by the server/UI.
 sieve_enabled = true
@@ -102,6 +115,8 @@ If the mail host settings are omitted, RustBox uses `localhost` with IMAP `993`
 
 Mail-size limits are intentionally separate. `max_attachment_size_mb` applies to each raw uploaded file, while `max_message_size_mb` is checked against the final RFC822/MIME byte stream immediately before SMTP submission. The latter therefore includes message bodies, headers, MIME boundaries, base64 expansion, inline CID parts and OpenPGP transformations. The composer displays only an estimate; the server-side final-MIME check is authoritative.
 
+Attachments are streamed to blob storage on upload, but sending a message or saving an IMAP draft snapshot has to hold them in memory while the MIME message is built. RustBox therefore (1) rejects an attachment set whose base64-encoded size cannot fit `max_message_size_mb` with `413` before any file is read into memory, and also while an upload is still streaming, and (2) allows only `max_concurrent_message_builds` such operations at the same time; further requests wait up to `message_build_wait_secs` and then receive `503`. Peak RAM for these operations is roughly `max_concurrent_message_builds` x 4 x `max_message_size_mb`. Fully streamed MIME assembly is not implemented.
+
 ## Database, storage, search and cluster traffic
 
 `database_backend = "sqlite" | "mysql" | "pgsql"` selects only the authoritative SQL database. It does not force or forbid local blob/search storage. In particular, PostgreSQL/MySQL are valid in a single-node installation together with `storage.backend="filesystem"` and `search.backend="local_tantivy"`.

RELEASE-MANIFEST.txt

@@ -1,6 +1,16 @@
-RustBox 0.2.20 release manifest
+RustBox 0.2.22 release manifest
 
-0.2.20 release changes and retained feature set:
+0.2.22 release changes:
+- adds message snooze: snoozing a message hides it client-side from its folder's current view until the chosen wake time, without touching server-side folder pagination/count SQL; `snoozed_messages` is a local-only cache table with no IMAP side effects, so a snoozed message is unaffected on any other client
+- adds an "Undo Send" window: when `undo_send_window_secs > 0` (default 8s, max 120s), a submitted message is held in memory and only dispatched to SMTP after the window elapses unless cancelled; nothing is persisted, so a server restart during the window loses the staged send the same way an in-flight SMTP connection would be lost
+- adds `GET/DELETE /messages/send/{pending_send_id}` to poll or cancel a staged send, and `POST/DELETE /messages/{folder}/{uid}/snooze`, `GET /messages/snoozed`, `GET /folders/{name}/snoozed-uids` for snooze
+
+0.2.21 release changes and retained feature set:
+- adds configurable login brute-force protection (`[login_rate_limit]`): per-IP token bucket plus per-mailbox and per-IP failed-attempt lockouts with exponential back-off; locked attempts return 429 + Retry-After before any IMAP connection
+- the public `/api/auth/policy` GET no longer consumes the per-IP login budget
+- adds `cookie_secure = auto | always | never`; `auto` sets the cookie `Secure` attribute only for requests that really arrived over HTTPS, so plain-HTTP installs keep working
+- adds attachment memory guards: attachment sets that cannot fit `max_message_size_mb` once MIME-encoded are rejected with 413 from stored sizes before any file is loaded (send, IMAP draft snapshot, attach-message, streaming upload), and `max_concurrent_message_builds` / `message_build_wait_secs` bound how many requests hold attachments in RAM at once
+- adds gmail-style message row opening: Ctrl/Cmd+click opens a message in a new tab, Shift+click opens it in a popup window, both deep-linked (outside selection mode; existing shift/ctrl selection behavior while selecting is unchanged)
 - fixes the Axum route visibility mismatch for `AttachMessageSourceRequest`, allowing the forward-as-attachment handler to compile from `routes::mod`
 - falls back to IMAP `INTERNALDATE` for messages with a missing/invalid message `Date` and repairs cached missing dates when opening a folder
 - forwards a message as a real server-created `message/rfc822` `.eml` draft attachment
@@ -64,7 +74,8 @@ Database/schema:
 - compatibility baseline is V050; former V047-V050 changes are consolidated into `schema.sql` and their standalone migrations are removed
 - databases older than V050 must be upgraded with a V050-capable RustBox release before using this build
 - V051 adds `display_preferences.adaptive_email_colors` and `mail_preferences.message_loading_mode` to existing V050 tenants
-- next migration number: V052
+- V052 adds `snoozed_messages` (local-only cache state, no IMAP side effects) to existing V051 tenants
+- next migration number: V053
 
 Docker examples:
 - docker/compose-single-sqlite.yml
@@ -74,14 +85,14 @@ Docker examples:
 
 Operations/docs:
 - standalone `scripts/migrate_roundcube.py` imports Roundcube contacts/identities using RustBox config.toml and supports SQLite/MySQL/PostgreSQL targets
-- README.md documents 0.2.20 configuration
+- README.md documents 0.2.22 configuration
 - docker/README.md documents Compose variants
 - docs/STORAGE_SEARCH_OPERATIONS.md documents failure modes, shared-storage requirements and migration behavior
 - TODO.md leaves live SILO/MinIO/AWS/Ceph and real multi-node acceptance validation explicitly pending
 
 Build/release metadata:
 - `scripts/package-release.sh` runs the full Rust release gate before creating ZIP/SHA256 artifacts
-- Cargo.toml version = 0.2.20
+- Cargo.toml version = 0.2.22
 - rust-toolchain.toml pins Rust 1.99.1
 - Cargo.lock is retained for reproducible application builds; the release gate generates it only when missing
 - CI and scripts/build-release.sh use the retained Cargo.lock (generating it only if missing), then run locked tests/Clippy/release build

RELEASE-VALIDATION.txt

@@ -1,6 +1,16 @@
-RustBox 0.2.20 - final source validation
+RustBox 0.2.22 - final source validation
 
-0.2.20 scope:
+0.2.22 scope:
+- adds message snooze (`snoozed_messages`, V052): hides a message client-side from its current folder view until a chosen wake time; purely client-side hiding, no server-side pagination/count SQL changes, no IMAP side effects
+- adds an in-memory "Undo Send" window (`undo_send_window_secs`, default 8s, max 120s): a submitted message is staged and only dispatched to SMTP once the window elapses unless cancelled first; not persisted, so a restart during the window drops the staged send
+- new endpoints: `GET/DELETE /messages/send/{pending_send_id}`, `POST/DELETE /messages/{folder}/{uid}/snooze`, `GET /messages/snoozed`, `GET /folders/{name}/snoozed-uids`
+
+0.2.21 scope:
+- adds configurable login brute-force protection (`[login_rate_limit]`): per-IP token bucket plus per-mailbox and per-IP failed-attempt lockouts with exponential back-off; locked attempts return 429 + Retry-After before any IMAP connection
+- the public `/api/auth/policy` GET no longer consumes the per-IP login budget
+- adds `cookie_secure = auto | always | never`; `auto` sets the cookie `Secure` attribute only for requests that really arrived over HTTPS, so plain-HTTP installs keep working
+- adds attachment memory guards: attachment sets that cannot fit `max_message_size_mb` once MIME-encoded are rejected with 413 from stored sizes before any file is loaded (send, IMAP draft snapshot, attach-message, streaming upload), and `max_concurrent_message_builds` / `message_build_wait_secs` bound how many requests hold attachments in RAM at once
+- adds gmail-style message row opening: Ctrl/Cmd+click opens a message in a new tab, Shift+click opens it in a popup window, both deep-linked (outside selection mode; existing shift/ctrl selection behavior while selecting is unchanged)
 - fixes the Axum route visibility mismatch for `AttachMessageSourceRequest`, allowing the forward-as-attachment handler to compile from `routes::mod`
 - falls back to IMAP `INTERNALDATE` for messages with a missing/invalid message `Date` and repairs cached missing dates when opening a folder
 - forwards a message as a real server-created `message/rfc822` `.eml` draft attachment
@@ -35,16 +45,16 @@ RustBox 0.2.20 - final source validation
 - PDF attachment preview uses the authenticated inline URL for Safari/iPhone compatibility
 - Composing shows only compact attachment/message size-limit values on one line
 - 0.2.9 realtime notification gating, browser shortcut preservation and 300-message defaults remain intact
-- V047-V050 are consolidated into compatibility baseline V050; V051 migrates existing tenants with adaptive HTML-mail colors and mailbox loading mode; V052 is next
-- version metadata identifies 0.2.20
+- V047-V050 are consolidated into compatibility baseline V050; V051 migrates existing tenants with adaptive HTML-mail colors and mailbox loading mode; V052 adds `snoozed_messages` to existing V051 tenants; V053 is next
+- version metadata identifies 0.2.22
 
 Completed in this environment:
-- offline release validator: scripts/validate-release-static.py (421/421 checks passed)
+- offline release validator: scripts/validate-release-static.py (424/424 checks passed)
 - browser JavaScript assembled in manifest order passes `node --check`
 - all JSON files parse successfully
 - Python helper scripts compile successfully
 - shell scripts pass `bash -n`
-- release metadata consistently identifies 0.2.20
+- release metadata consistently identifies 0.2.22
 - V050 baseline consolidation plus the V051 adaptive-colors/mailbox-loading migration are validated offline
 
 

config.dev.toml

@@ -2,6 +2,7 @@
 host = "127.0.0.1"
 port = 3001
 environment = "development"
+cookie_secure = "auto"
 # Global light/dark theme: system | dark | light
 default_theme = "system"
 # Global interface style used by the login screen and by accounts set to
@@ -38,6 +39,18 @@ tls_enabled = true
 # Per-file raw upload limit and final RFC822/MIME MTA limit (MiB).
 max_attachment_size_mb = 10
 max_message_size_mb = 50
+# Memory guard for messages with attachments. Sending a message or saving an IMAP
+# draft snapshot loads every attachment into RAM and the MIME builder keeps several
+# copies (about 3-4x the message size). Attachment sets that cannot fit
+# max_message_size_mb are rejected with 413 before any file is read, and at most
+# max_concurrent_message_builds requests may hold attachments in memory at once;
+# the others wait up to message_build_wait_secs and then get 503.
+# Rough peak RAM = max_concurrent_message_builds x 4 x max_message_size_mb.
+max_concurrent_message_builds = 4
+message_build_wait_secs = 30
+
+# "Undo Send" window in seconds (0 disables; max 120). See config.example.toml.
+undo_send_window_secs = 8
 
 # Optional administrator-facing features.
 sieve_enabled = true

config.example.toml

@@ -2,6 +2,12 @@
 host = "127.0.0.1"
 port = 3001
 environment = "production"
+# Secure attribute of session cookies: auto | always | never.
+# auto (default) sets Secure only when the browser reached RustBox over HTTPS:
+# X-Forwarded-Proto / Forwarded: proto= / X-Forwarded-Ssl from a trusted proxy,
+# otherwise the scheme of the browser's Origin/Referer. Plain-HTTP installations
+# therefore keep working. Use "always" behind HTTPS if your proxy strips headers.
+cookie_secure = "auto"
 # Global light/dark theme: system | dark | light
 default_theme = "system"
 # Global interface style used by the login screen and by accounts set to
@@ -51,6 +57,22 @@ tls_enabled = true
 max_attachment_size_mb = 10
 # Maximum size of the complete RFC822/MIME message submitted to the MTA (MiB).
 max_message_size_mb = 50
+# Memory guard for messages with attachments. Sending a message or saving an IMAP
+# draft snapshot loads every attachment into RAM and the MIME builder keeps several
+# copies (about 3-4x the message size). Attachment sets that cannot fit
+# max_message_size_mb are rejected with 413 before any file is read, and at most
+# max_concurrent_message_builds requests may hold attachments in memory at once;
+# the others wait up to message_build_wait_secs and then get 503.
+# Rough peak RAM = max_concurrent_message_builds x 4 x max_message_size_mb.
+max_concurrent_message_builds = 4
+message_build_wait_secs = 30
+
+# "Undo Send" window in seconds. A submitted message is held in memory (not
+# persisted) for this long before it is actually dispatched to SMTP, so the
+# sender can cancel it. 0 disables the feature and sends immediately. Must be
+# <= 120; keep this short, since a server restart during the window loses the
+# staged send.
+undo_send_window_secs = 8
 
 # Optional reverse-proxy subpath, e.g. "/mail".
 # base_path = "/mail"
@@ -97,6 +119,36 @@ pgp_max_key_bytes = 1048576
 # Private-key export is deliberately disabled unless the administrator opts in.
 pgp_allow_private_export = false
 
+# Login brute-force protection (POST /api/auth/login). Enabled by default.
+# Environment overrides use a double underscore, e.g.
+# LOGIN_RATE_LIMIT__ACCOUNT_MAX_FAILURES=10 or LOGIN_RATE_LIMIT__ENABLED=false.
+# Client IPs are taken from X-Forwarded-For only when the peer is in trusted_proxies.
+# State is kept in memory on each node: behind a load balancer every node counts
+# separately, so use sticky routing or lower thresholds in cluster mode.
+[login_rate_limit]
+enabled = true
+# Per-IP token bucket: up to ip_burst attempts at once, then one new attempt
+# every ip_replenish_secs seconds. Requests over the limit get HTTP 429.
+ip_burst = 5
+ip_replenish_secs = 12
+# Failed logins counted inside failure_window_secs before a lockout.
+# account_max_failures: per mailbox (case-insensitive), from any IP.
+# ip_max_failures: per client IP, across all mailboxes (password spraying).
+# 0 disables that lockout type.
+account_max_failures = 5
+ip_max_failures = 20
+failure_window_secs = 900
+# First lockout length; every consecutive lockout of the same key doubles it
+# up to max_lockout_secs. Locked attempts are refused before contacting IMAP.
+# Trade-off: an attacker can keep a known mailbox locked for webmail logins
+# (IMAP/SMTP clients are unaffected), so keep max_lockout_secs moderate.
+lockout_secs = 300
+max_lockout_secs = 3600
+# IPs/CIDRs exempt from the per-IP lockout (account lockouts still apply).
+exempt_networks = []
+# Memory cap per tracking table (accounts, IPs).
+max_tracked_keys = 100000
+
 [storage]
 backend = "filesystem" # filesystem | s3
 # path = "/var/lib/rustbox/blobs" # defaults to data_dir for filesystem

docs/IMPLEMENTATION_STATUS.md

@@ -1,7 +1,21 @@
-# RustBox 0.2.20 - implementation status
+# RustBox 0.2.22 - implementation status
 
 - Draft saves are realtime-silent: Drafts folder/list updates continue, but saving a draft does not surface as a new-mail notification.
-This file tracks the `0.2.20` source snapshot. Storage/search scope and outstanding acceptance work are tracked in `TODO.md`. A feature is only listed as implemented when working code exists in this source tree; partial items are called out explicitly.
+This file tracks the `0.2.22` source snapshot. Storage/search scope and outstanding acceptance work are tracked in `TODO.md`. A feature is only listed as implemented when working code exists in this source tree; partial items are called out explicitly.
+
+## 0.2.22 snooze and undo send
+
+- Adds message snooze: `snoozed_messages` (migration V052) is a local-only cache table — snoozing a message records a wake time and the client hides that message from its current folder view until then, via `GET /folders/{name}/snoozed-uids`; it has no IMAP side effects and does not touch server-side folder pagination/count SQL in `routes/messages/mod.rs`. `POST/DELETE /messages/{folder}/{uid}/snooze` set/clear a snooze, and `GET /messages/snoozed` lists everything currently sleeping across folders for the "View snoozed messages…" dialog. UI: a "Snooze…" context-menu entry and the `b` shortcut (message open) prompt for a duration; `Shift+B` opens the snoozed-messages list.
+- Adds an "Undo Send" window: a new `undo_send_window_secs` config knob (default 8, max 120 seconds; 0 disables it and restores immediate synchronous send). When enabled, a submitted message is staged in an in-memory `UndoSendRegistry` (`src/undo_send.rs`) instead of being dispatched immediately; the HTTP response returns right away with `status: "pending"`, and a delayed task actually sends the message once the window elapses unless cancelled first. `GET /messages/send/{pending_send_id}` polls status (`pending`/`dispatching`/`sent`/`cancelled`/`failed`); `DELETE /messages/send/{pending_send_id}` cancels a still-pending send. Nothing is persisted: a server restart during the window loses the staged send, the same as an in-flight SMTP connection would be lost. The composer shows a toast with an "Undo" action and live countdown for the window.
+- Known limitation: a brand-new, never-autosaved compose that is sent and then left un-undone relies on the existing autosave/draft-recovery mechanism for recovery if the dispatch itself fails; this is not a new guarantee beyond what autosave already provides.
+
+## 0.2.21 login hardening
+
+- Adds configurable login brute-force protection (`[login_rate_limit]`): per-IP token bucket plus per-mailbox and per-IP failed-attempt lockouts with exponential back-off; locked attempts return 429 + Retry-After before any IMAP connection
+- The public `/api/auth/policy` GET no longer consumes the per-IP login budget
+- Adds `cookie_secure = auto | always | never`; `auto` sets the cookie `Secure` attribute only for requests that really arrived over HTTPS, so plain-HTTP installs keep working
+- Adds attachment memory guards: attachment sets that cannot fit `max_message_size_mb` once MIME-encoded are rejected with 413 from stored sizes before any file is loaded (send, IMAP draft snapshot, attach-message, streaming upload), and `max_concurrent_message_builds` / `message_build_wait_secs` bound how many requests hold attachments in RAM at once
+- Adds Gmail-style message row opening: Ctrl/Cmd+click opens a message in a new tab, Shift+click opens it in a popup window, both deep-linked (outside selection mode; existing shift/ctrl selection behavior while selecting is unchanged)
 
 ## 0.2.20 browser mail UX
 

migrations/README.md

@@ -23,7 +23,13 @@ V051 adds the preferences introduced in 0.2.16:
 
 Fresh installations already contain the V051 columns in `schema.sql` and are registered at the latest schema version. Existing V050 tenants execute `V051__adaptive_email_colors_and_message_loading_mode.sql` before application queries use the new columns.
 
-The next migration number is **V052**.
+## V052 — RustBox 0.2.22
+
+V052 adds the `snoozed_messages` table used by the Snooze feature introduced in 0.2.22: a message can be hidden from its folder listing in the client until a chosen wake time, without being moved on the real IMAP server. The table is local cache state only (no IMAP side effects) and has no foreign keys, matching `message_tags`' existing exemption from forward-referencing foreign keys in the MySQL/PostgreSQL schemas.
+
+Fresh installations already contain `snoozed_messages` in `schema.sql` and are registered at the latest schema version. Existing V051 tenants execute `V052__snooze.sql`.
+
+The next migration number is **V053**.
 
 ## Migration rules
 

migrations/mysql/V052__snooze.sql

@@ -0,0 +1,9 @@
+CREATE TABLE {{p}}snoozed_messages (
+    id VARCHAR(64) PRIMARY KEY,
+    message_uid BIGINT NOT NULL,
+    message_folder VARCHAR(512) NOT NULL,
+    wake_at BIGINT NOT NULL,
+    created_at VARCHAR(64) NOT NULL DEFAULT (CAST(CURRENT_TIMESTAMP AS CHAR)),
+    UNIQUE KEY idx_snoozed_messages_unique (message_uid, message_folder),
+    INDEX idx_snoozed_messages_wake (wake_at)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

migrations/mysql/schema.sql

@@ -1,7 +1,7 @@
 -- RustBox 0.2.0 MySQL schema.
 -- One physical database contains global sessions plus isolated per-account tables.
 -- Application tables are materialized by replacing {{p}} with a collision-checked prefix.
--- Squashed compatibility baseline: V050; current schema: V051.
+-- Squashed compatibility baseline: V050; current schema: V052.
 
 -- RUSTBOX:GLOBAL-BEGIN
 CREATE TABLE IF NOT EXISTS rustbox_accounts (
@@ -406,6 +406,16 @@ CREATE TABLE {{p}}saved_searches (
     updated_at VARCHAR(64) NOT NULL DEFAULT (CAST(CURRENT_TIMESTAMP AS CHAR))
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
 
+CREATE TABLE {{p}}snoozed_messages (
+    id VARCHAR(64) PRIMARY KEY,
+    message_uid BIGINT NOT NULL,
+    message_folder VARCHAR(512) NOT NULL,
+    wake_at BIGINT NOT NULL,
+    created_at VARCHAR(64) NOT NULL DEFAULT (CAST(CURRENT_TIMESTAMP AS CHAR)),
+    UNIQUE KEY idx_snoozed_messages_unique (message_uid, message_folder),
+    INDEX idx_snoozed_messages_wake (wake_at)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+
 CREATE TABLE {{p}}special_folders (
     role VARCHAR(255) PRIMARY KEY,
     folder_name TEXT NOT NULL,

migrations/pgsql/V052__snooze.sql

@@ -0,0 +1,10 @@
+CREATE TABLE {{p}}snoozed_messages (
+    id TEXT PRIMARY KEY,
+    message_uid BIGINT NOT NULL,
+    message_folder TEXT NOT NULL,
+    wake_at BIGINT NOT NULL,
+    created_at TEXT NOT NULL DEFAULT (CURRENT_TIMESTAMP::text),
+    UNIQUE (message_uid, message_folder)
+);
+
+CREATE INDEX {{p}}idx_snoozed_messages_wake ON {{p}}snoozed_messages(wake_at);

migrations/pgsql/schema.sql

@@ -1,7 +1,7 @@
 -- RustBox 0.2.0 PostgreSQL schema.
 -- One physical database contains global sessions plus isolated per-account tables.
 -- Application tables are materialized by replacing {{p}} with a collision-checked prefix.
--- Squashed compatibility baseline: V050; current schema: V051.
+-- Squashed compatibility baseline: V050; current schema: V052.
 
 -- RUSTBOX:GLOBAL-BEGIN
 CREATE TABLE IF NOT EXISTS rustbox_accounts (
@@ -408,6 +408,15 @@ CREATE TABLE {{p}}saved_searches (
     updated_at TEXT NOT NULL DEFAULT (CURRENT_TIMESTAMP::text)
 );
 
+CREATE TABLE {{p}}snoozed_messages (
+    id TEXT PRIMARY KEY,
+    message_uid BIGINT NOT NULL,
+    message_folder TEXT NOT NULL,
+    wake_at BIGINT NOT NULL,
+    created_at TEXT NOT NULL DEFAULT (CURRENT_TIMESTAMP::text),
+    UNIQUE (message_uid, message_folder)
+);
+
 CREATE TABLE {{p}}special_folders (
     role TEXT PRIMARY KEY,
     folder_name TEXT NOT NULL,
@@ -458,6 +467,8 @@ CREATE INDEX {{p}}idx_messages_in_reply_to ON {{p}}messages (in_reply_to);
 CREATE INDEX {{p}}idx_messages_message_id ON {{p}}messages (message_id);
 CREATE INDEX {{p}}idx_pgp_keys_email ON {{p}}pgp_keys (lower(email));
 CREATE UNIQUE INDEX {{p}}idx_saved_searches_name ON {{p}}saved_searches (name);
+
+CREATE INDEX {{p}}idx_snoozed_messages_wake ON {{p}}snoozed_messages(wake_at);
 CREATE UNIQUE INDEX {{p}}idx_tags_imap_keyword ON {{p}}tags (imap_keyword) WHERE imap_keyword <> '';
 
 -- RUSTBOX:TENANT-END

migrations/sqlite/V052__snooze.sql

@@ -0,0 +1,10 @@
+CREATE TABLE {{p}}snoozed_messages (
+    id TEXT PRIMARY KEY,
+    message_uid INTEGER NOT NULL,
+    message_folder TEXT NOT NULL,
+    wake_at INTEGER NOT NULL,
+    created_at TEXT NOT NULL DEFAULT (datetime('now')),
+    UNIQUE (message_uid, message_folder)
+);
+
+CREATE INDEX {{p}}idx_snoozed_messages_wake ON {{p}}snoozed_messages(wake_at);

migrations/sqlite/schema.sql

@@ -1,7 +1,7 @@
 -- RustBox 0.2.0 SQLite schema.
 -- One physical database contains global sessions plus isolated per-account tables.
 -- Application tables are materialized from the tenant section by replacing {{p}}.
--- Squashed compatibility baseline: V050; current schema: V051.
+-- Squashed compatibility baseline: V050; current schema: V052.
 
 -- RUSTBOX:GLOBAL-BEGIN
 CREATE TABLE IF NOT EXISTS rustbox_accounts (
@@ -320,6 +320,15 @@ CREATE TABLE {{p}}saved_searches (
     updated_at TEXT NOT NULL DEFAULT (datetime('now'))
 );
 
+CREATE TABLE {{p}}snoozed_messages (
+    id TEXT PRIMARY KEY,
+    message_uid INTEGER NOT NULL,
+    message_folder TEXT NOT NULL,
+    wake_at INTEGER NOT NULL,
+    created_at TEXT NOT NULL DEFAULT (datetime('now')),
+    UNIQUE (message_uid, message_folder)
+);
+
 CREATE TABLE {{p}}special_folders (
     role TEXT PRIMARY KEY CHECK(role IN ('sent','drafts','trash','junk','archive')),
     folder_name TEXT NOT NULL,
@@ -374,6 +383,8 @@ CREATE INDEX {{p}}idx_pgp_keys_email ON {{p}}pgp_keys(lower(email));
 
 CREATE UNIQUE INDEX {{p}}idx_saved_searches_name ON {{p}}saved_searches(name COLLATE NOCASE);
 
+CREATE INDEX {{p}}idx_snoozed_messages_wake ON {{p}}snoozed_messages(wake_at);
+
 CREATE UNIQUE INDEX {{p}}idx_tags_imap_keyword ON {{p}}tags(imap_keyword) WHERE imap_keyword <> '';
 
 -- RUSTBOX:TENANT-END

packaging/rustbox.toml

@@ -10,6 +10,12 @@
 host = "0.0.0.0"
 port = 3001
 environment = "production"
+# Secure attribute of session cookies: auto | always | never.
+# auto (default) sets Secure only when the browser reached RustBox over HTTPS:
+# X-Forwarded-Proto / Forwarded: proto= / X-Forwarded-Ssl from a trusted proxy,
+# otherwise the scheme of the browser's Origin/Referer. Plain-HTTP installations
+# therefore keep working. Use "always" behind HTTPS if your proxy strips headers.
+cookie_secure = "auto"
 
 data_dir = "/var/lib/rustbox"
 log_dir = "/var/log/rustbox"
@@ -127,6 +133,18 @@ max_attachment_size_mb = 50
 
 # Maximum complete RFC822/MIME message size in MiB.
 max_message_size_mb = 100
+# Memory guard for messages with attachments. Sending a message or saving an IMAP
+# draft snapshot loads every attachment into RAM and the MIME builder keeps several
+# copies (about 3-4x the message size). Attachment sets that cannot fit
+# max_message_size_mb are rejected with 413 before any file is read, and at most
+# max_concurrent_message_builds requests may hold attachments in memory at once;
+# the others wait up to message_build_wait_secs and then get 503.
+# Rough peak RAM = max_concurrent_message_builds x 4 x max_message_size_mb.
+max_concurrent_message_builds = 4
+message_build_wait_secs = 30
+
+# "Undo Send" window in seconds (0 disables; max 120). See config.example.toml.
+undo_send_window_secs = 8
 
 
 # -----------------------------------------------------------------------------
@@ -210,6 +228,41 @@ pgp_allow_private_export = true
 #
 # pgp_enabled = false
 
+
+# -----------------------------------------------------------------------------
+# Login brute-force protection
+# -----------------------------------------------------------------------------
+
+# Login brute-force protection (POST /api/auth/login). Enabled by default.
+# Environment overrides use a double underscore, e.g.
+# LOGIN_RATE_LIMIT__ACCOUNT_MAX_FAILURES=10 or LOGIN_RATE_LIMIT__ENABLED=false.
+# Client IPs are taken from X-Forwarded-For only when the peer is in trusted_proxies.
+# State is kept in memory on each node: behind a load balancer every node counts
+# separately, so use sticky routing or lower thresholds in cluster mode.
+[login_rate_limit]
+enabled = true
+# Per-IP token bucket: up to ip_burst attempts at once, then one new attempt
+# every ip_replenish_secs seconds. Requests over the limit get HTTP 429.
+ip_burst = 5
+ip_replenish_secs = 12
+# Failed logins counted inside failure_window_secs before a lockout.
+# account_max_failures: per mailbox (case-insensitive), from any IP.
+# ip_max_failures: per client IP, across all mailboxes (password spraying).
+# 0 disables that lockout type.
+account_max_failures = 5
+ip_max_failures = 20
+failure_window_secs = 900
+# First lockout length; every consecutive lockout of the same key doubles it
+# up to max_lockout_secs. Locked attempts are refused before contacting IMAP.
+# Trade-off: an attacker can keep a known mailbox locked for webmail logins
+# (IMAP/SMTP clients are unaffected), so keep max_lockout_secs moderate.
+lockout_secs = 300
+max_lockout_secs = 3600
+# IPs/CIDRs exempt from the per-IP lockout (account lockouts still apply).
+exempt_networks = []
+# Memory cap per tracking table (accounts, IPs).
+max_tracked_keys = 100000
+
 [storage]
 
 # filesystem | s3

src/auth/login_guard.rs

@@ -0,0 +1,512 @@
+//! Login brute-force protection.
+//!
+//! The per-IP token bucket (`tower_governor`, configured in `routes::mod`) caps the
+//! raw request rate on `POST /api/auth/login`. This module adds failure-based
+//! lockouts on top of it:
+//!
+//! * per account (case-insensitive e-mail, regardless of client IP) — stops slow,
+//!   distributed password guessing against one mailbox;
+//! * per client IP (any account) — stops password spraying from one source.
+//!
+//! Consecutive lockouts of the same key double the lockout time up to
+//! `max_lockout_secs`. A locked request is rejected before RustBox opens an IMAP
+//! connection, so brute force does not reach (or trigger lockouts on) the mail
+//! server. State is in memory and per node; see `[login_rate_limit]` in the
+//! configuration for all knobs.
+
+use std::collections::HashMap;
+use std::hash::Hash;
+use std::net::IpAddr;
+use std::sync::atomic::{AtomicU64, Ordering};
+use std::sync::{Mutex, MutexGuard};
+use std::time::{Duration, Instant};
+
+use ipnet::IpNet;
+
+use crate::config::LoginRateLimitConfig;
+
+/// Expired entries are swept every N recorded failures.
+const PRUNE_EVERY: u64 = 256;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum LockScope {
+    Account,
+    Ip,
+}
+
+impl LockScope {
+    pub fn as_str(self) -> &'static str {
+        match self {
+            Self::Account => "account",
+            Self::Ip => "ip",
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct LoginBlocked {
+    pub retry_after: Duration,
+    pub scope: LockScope,
+}
+
+impl LoginBlocked {
+    /// Whole seconds for the `Retry-After` header (rounded up, at least 1).
+    pub fn retry_after_secs(&self) -> u64 {
+        let secs = self.retry_after.as_secs();
+        let secs = if self.retry_after.subsec_nanos() > 0 {
+            secs.saturating_add(1)
+        } else {
+            secs
+        };
+        secs.max(1)
+    }
+}
+
+#[derive(Debug, Clone, Copy)]
+struct Policy {
+    failure_window: Duration,
+    lockout: Duration,
+    max_lockout: Duration,
+    max_tracked_keys: usize,
+}
+
+impl Policy {
+    /// Lockout duration for the n-th consecutive lockout (n >= 1).
+    fn lockout_for(&self, lockouts: u32) -> Duration {
+        let exponent = lockouts.saturating_sub(1).min(20);
+        self.lockout
+            .saturating_mul(1u32 << exponent)
+            .min(self.max_lockout)
+    }
+
+    /// Idle time after which an unlocked entry (and its back-off history) is dropped.
+    fn idle_ttl(&self) -> Duration {
+        self.failure_window.max(self.max_lockout)
+    }
+}
+
+#[derive(Debug, Clone)]
+struct FailureEntry {
+    window_start: Instant,
+    failures: u32,
+    lockouts: u32,
+    locked_until: Option<Instant>,
+    last_activity: Instant,
+}
+
+impl FailureEntry {
+    fn new(now: Instant) -> Self {
+        Self {
+            window_start: now,
+            failures: 0,
+            lockouts: 0,
+            locked_until: None,
+            last_activity: now,
+        }
+    }
+
+    fn remaining_lock(&self, now: Instant) -> Option<Duration> {
+        self.locked_until
+            .and_then(|until| until.checked_duration_since(now))
+            .filter(|remaining| !remaining.is_zero())
+    }
+}
+
+struct FailureTracker<K> {
+    entries: Mutex<HashMap<K, FailureEntry>>,
+    /// 0 disables this tracker.
+    max_failures: u32,
+}
+
+impl<K: Eq + Hash> FailureTracker<K> {
+    fn new(max_failures: u32) -> Self {
+        Self {
+            entries: Mutex::new(HashMap::new()),
+            max_failures,
+        }
+    }
+
+    fn lock(&self) -> MutexGuard<'_, HashMap<K, FailureEntry>> {
+        self.entries
+            .lock()
+            .unwrap_or_else(|poisoned| poisoned.into_inner())
+    }
+
+    fn remaining_lock(&self, key: &K, now: Instant) -> Option<Duration> {
+        if self.max_failures == 0 {
+            return None;
+        }
+        self.lock()
+            .get(key)
+            .and_then(|entry| entry.remaining_lock(now))
+    }
+
+    /// Records one failure; returns the new lockout duration if this failure
+    /// triggered a lockout.
+    fn record_failure(&self, key: K, now: Instant, policy: &Policy) -> Option<Duration> {
+        if self.max_failures == 0 {
+            return None;
+        }
+        let mut entries = self.lock();
+        if !entries.contains_key(&key) && entries.len() >= policy.max_tracked_keys {
+            Self::prune_locked(&mut entries, now, policy);
+            if entries.len() >= policy.max_tracked_keys {
+                tracing::warn!(
+                    tracked = entries.len(),
+                    "login rate limiter table is full; new key not tracked"
+                );
+                return None;
+            }
+        }
+
+        let entry = entries.entry(key).or_insert_with(|| FailureEntry::new(now));
+        if entry.remaining_lock(now).is_some() {
+            // Requests that were already in flight when the lock was set.
+            entry.last_activity = now;
+            return None;
+        }
+        if entry.lockouts > 0 && now.duration_since(entry.last_activity) >= policy.idle_ttl() {
+            entry.lockouts = 0;
+        }
+        if now.duration_since(entry.window_start) >= policy.failure_window {
+            entry.window_start = now;
+            entry.failures = 0;
+        }
+
+        entry.failures = entry.failures.saturating_add(1);
+        entry.last_activity = now;
+        if entry.failures < self.max_failures {
+            return None;
+        }
+
+        entry.lockouts = entry.lockouts.saturating_add(1);
+        let duration = policy.lockout_for(entry.lockouts);
+        entry.locked_until = Some(now + duration);
+        entry.failures = 0;
+        entry.window_start = now;
+        Some(duration)
+    }
+
+    fn clear(&self, key: &K) {
+        self.lock().remove(key);
+    }
+
+    fn prune(&self, now: Instant, policy: &Policy) {
+        Self::prune_locked(&mut self.lock(), now, policy);
+    }
+
+    fn prune_locked(entries: &mut HashMap<K, FailureEntry>, now: Instant, policy: &Policy) {
+        let ttl = policy.idle_ttl();
+        entries.retain(|_, entry| {
+            entry.remaining_lock(now).is_some() || now.duration_since(entry.last_activity) < ttl
+        });
+    }
+
+    #[cfg(test)]
+    fn len(&self) -> usize {
+        self.lock().len()
+    }
+}
+
+pub struct LoginGuard {
+    enabled: bool,
+    policy: Policy,
+    exempt_networks: Vec<IpNet>,
+    accounts: FailureTracker<String>,
+    ips: FailureTracker<IpAddr>,
+    recorded_failures: AtomicU64,
+}
+
+impl LoginGuard {
+    pub fn from_config(config: &LoginRateLimitConfig) -> Self {
+        let exempt_networks = config.parsed_exempt_networks().unwrap_or_else(|error| {
+            // AppConfig::validate rejects this at startup; never fail open silently.
+            tracing::error!(%error, "ignoring invalid login_rate_limit.exempt_networks");
+            Vec::new()
+        });
+        Self {
+            enabled: config.enabled,
+            policy: Policy {
+                failure_window: Duration::from_secs(config.failure_window_secs.max(1)),
+                lockout: Duration::from_secs(config.lockout_secs.max(1)),
+                max_lockout: Duration::from_secs(
+                    config.max_lockout_secs.max(config.lockout_secs).max(1),
+                ),
+                max_tracked_keys: config.max_tracked_keys.max(1),
+            },
+            exempt_networks,
+            accounts: FailureTracker::new(config.account_max_failures),
+            ips: FailureTracker::new(config.ip_max_failures),
+            recorded_failures: AtomicU64::new(0),
+        }
+    }
+
+    /// Normalized account key: the same mailbox must not get a fresh budget by
+    /// changing letter case or adding whitespace.
+    pub fn account_key(email: &str) -> String {
+        email.trim().to_lowercase()
+    }
+
+    fn ip_is_tracked(&self, ip: &IpAddr) -> bool {
+        !self
+            .exempt_networks
+            .iter()
+            .any(|network| network.contains(ip))
+    }
+
+    /// Returns `Err` when the account or client IP is currently locked out.
+    pub fn check(&self, email: &str, ip: IpAddr) -> Result<(), LoginBlocked> {
+        self.check_at(email, ip, Instant::now())
+    }
+
+    /// Records a failed login (wrong credentials). Returns the lockout that this
+    /// failure triggered, if any, so the caller can log it.
+    pub fn record_failure(&self, email: &str, ip: IpAddr) -> Option<LoginBlocked> {
+        self.record_failure_at(email, ip, Instant::now())
+    }
+
+    /// Successful login resets the account's failure history. The IP history is
+    /// kept so an attacker cannot reset a spraying budget with their own account.
+    pub fn record_success(&self, email: &str) {
+        if self.enabled {
+            self.accounts.clear(&Self::account_key(email));
+        }
+    }
+
+    #[cfg(test)]
+    fn tracked_keys(&self) -> (usize, usize) {
+        (self.accounts.len(), self.ips.len())
+    }
+
+    fn check_at(&self, email: &str, ip: IpAddr, now: Instant) -> Result<(), LoginBlocked> {
+        if !self.enabled {
+            return Ok(());
+        }
+        let account = self
+            .accounts
+            .remaining_lock(&Self::account_key(email), now)
+            .map(|retry_after| LoginBlocked {
+                retry_after,
+                scope: LockScope::Account,
+            });
+        let ip = if self.ip_is_tracked(&ip) {
+            self.ips
+                .remaining_lock(&ip, now)
+                .map(|retry_after| LoginBlocked {
+                    retry_after,
+                    scope: LockScope::Ip,
+                })
+        } else {
+            None
+        };
+        match (account, ip) {
+            (Some(a), Some(i)) => Err(if a.retry_after >= i.retry_after { a } else { i }),
+            (Some(blocked), None) | (None, Some(blocked)) => Err(blocked),
+            (None, None) => Ok(()),
+        }
+    }
+
+    fn record_failure_at(&self, email: &str, ip: IpAddr, now: Instant) -> Option<LoginBlocked> {
+        if !self.enabled {
+            return None;
+        }
+        if self
+            .recorded_failures
+            .fetch_add(1, Ordering::Relaxed)
+            .is_multiple_of(PRUNE_EVERY)
+        {
+            self.accounts.prune(now, &self.policy);
+            self.ips.prune(now, &self.policy);
+        }
+
+        let account = self
+            .accounts
+            .record_failure(Self::account_key(email), now, &self.policy)
+            .map(|retry_after| LoginBlocked {
+                retry_after,
+                scope: LockScope::Account,
+            });
+        let ip = if self.ip_is_tracked(&ip) {
+            self.ips
+                .record_failure(ip, now, &self.policy)
+                .map(|retry_after| LoginBlocked {
+                    retry_after,
+                    scope: LockScope::Ip,
+                })
+        } else {
+            None
+        };
+        account.or(ip)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn config() -> LoginRateLimitConfig {
+        LoginRateLimitConfig {
+            account_max_failures: 3,
+            ip_max_failures: 5,
+            failure_window_secs: 60,
+            lockout_secs: 10,
+            max_lockout_secs: 40,
+            ..LoginRateLimitConfig::default()
+        }
+    }
+
+    fn ip(value: &str) -> IpAddr {
+        value.parse().unwrap()
+    }
+
+    #[test]
+    fn account_is_locked_after_max_failures_from_any_ip() {
+        let guard = LoginGuard::from_config(&config());
+        let t0 = Instant::now();
+        assert!(
+            guard
+                .record_failure_at("a@x.test", ip("192.0.2.1"), t0)
+                .is_none()
+        );
+        assert!(
+            guard
+                .record_failure_at("a@x.test", ip("192.0.2.2"), t0)
+                .is_none()
+        );
+        let locked = guard
+            .record_failure_at("A@X.test ", ip("192.0.2.3"), t0)
+            .expect("third failure locks the account");
+        assert_eq!(locked.scope, LockScope::Account);
+        assert_eq!(locked.retry_after, Duration::from_secs(10));
+
+        let blocked = guard
+            .check_at("a@x.test", ip("198.51.100.9"), t0 + Duration::from_secs(1))
+            .unwrap_err();
+        assert_eq!(blocked.scope, LockScope::Account);
+        assert_eq!(blocked.retry_after_secs(), 9);
+        assert!(
+            guard
+                .check_at("other@x.test", ip("198.51.100.9"), t0)
+                .is_ok()
+        );
+        assert!(
+            guard
+                .check_at("a@x.test", ip("198.51.100.9"), t0 + Duration::from_secs(10))
+                .is_ok()
+        );
+    }
+
+    #[test]
+    fn consecutive_lockouts_back_off_exponentially_up_to_the_cap() {
+        let guard = LoginGuard::from_config(&config());
+        let mut now = Instant::now();
+        let mut durations = Vec::new();
+        for _ in 0..4 {
+            let mut lock = None;
+            for _ in 0..3 {
+                lock = guard.record_failure_at("a@x.test", ip("192.0.2.1"), now);
+            }
+            let lock = lock.expect("lockout");
+            durations.push(lock.retry_after.as_secs());
+            now += lock.retry_after;
+        }
+        assert_eq!(durations, vec![10, 20, 40, 40]);
+    }
+
+    #[test]
+    fn success_clears_account_but_not_ip_history() {
+        let guard = LoginGuard::from_config(&config());
+        let t0 = Instant::now();
+        let attacker = ip("203.0.113.5");
+        for n in 0..4 {
+            guard.record_failure_at(&format!("victim{n}@x.test"), attacker, t0);
+        }
+        guard.record_failure_at("a@x.test", attacker, t0);
+        guard.record_success("a@x.test");
+        // 5th failure from the same IP (different accounts) locks the IP.
+        assert!(guard.check_at("new@x.test", attacker, t0).is_err());
+        assert_eq!(
+            guard
+                .check_at("new@x.test", attacker, t0)
+                .unwrap_err()
+                .scope,
+            LockScope::Ip
+        );
+        assert_eq!(guard.tracked_keys().0, 4);
+    }
+
+    #[test]
+    fn failures_outside_the_window_do_not_accumulate() {
+        let guard = LoginGuard::from_config(&config());
+        let t0 = Instant::now();
+        guard.record_failure_at("a@x.test", ip("192.0.2.1"), t0);
+        guard.record_failure_at("a@x.test", ip("192.0.2.1"), t0);
+        let later = t0 + Duration::from_secs(61);
+        assert!(
+            guard
+                .record_failure_at("a@x.test", ip("192.0.2.1"), later)
+                .is_none()
+        );
+        assert!(guard.check_at("a@x.test", ip("192.0.2.1"), later).is_ok());
+    }
+
+    #[test]
+    fn exempt_networks_skip_only_the_ip_lockout() {
+        let guard = LoginGuard::from_config(&LoginRateLimitConfig {
+            exempt_networks: vec!["10.0.0.0/8".to_string()],
+            ip_max_failures: 1,
+            ..config()
+        });
+        let t0 = Instant::now();
+        let internal = ip("10.1.2.3");
+        guard.record_failure_at("a@x.test", internal, t0);
+        assert!(guard.check_at("b@x.test", internal, t0).is_ok());
+        guard.record_failure_at("a@x.test", internal, t0);
+        guard.record_failure_at("a@x.test", internal, t0);
+        assert_eq!(
+            guard.check_at("a@x.test", internal, t0).unwrap_err().scope,
+            LockScope::Account
+        );
+    }
+
+    #[test]
+    fn zero_thresholds_and_disabled_guard_never_block() {
+        let guard = LoginGuard::from_config(&LoginRateLimitConfig {
+            account_max_failures: 0,
+            ip_max_failures: 0,
+            ..config()
+        });
+        let t0 = Instant::now();
+        for _ in 0..50 {
+            assert!(
+                guard
+                    .record_failure_at("a@x.test", ip("192.0.2.1"), t0)
+                    .is_none()
+            );
+        }
+        assert!(guard.check_at("a@x.test", ip("192.0.2.1"), t0).is_ok());
+
+        let disabled = LoginGuard::from_config(&LoginRateLimitConfig {
+            enabled: false,
+            ..config()
+        });
+        for _ in 0..50 {
+            disabled.record_failure_at("a@x.test", ip("192.0.2.1"), t0);
+        }
+        assert!(disabled.check_at("a@x.test", ip("192.0.2.1"), t0).is_ok());
+    }
+
+    #[test]
+    fn table_cap_bounds_memory() {
+        let guard = LoginGuard::from_config(&LoginRateLimitConfig {
+            max_tracked_keys: 100,
+            ip_max_failures: 0,
+            ..config()
+        });
+        let t0 = Instant::now();
+        for n in 0..500 {
+            guard.record_failure_at(&format!("u{n}@x.test"), ip("192.0.2.1"), t0);
+        }
+        assert_eq!(guard.tracked_keys().0, 100);
+    }
+}

src/auth/mod.rs

@@ -1,5 +1,6 @@
 pub mod csrf;
 pub mod imap_auth;
+pub mod login_guard;
 pub mod middleware;
 pub mod session;
 pub mod user_data;

src/config.rs

@@ -180,6 +180,125 @@ impl Default for SearchConfig {
     }
 }
 
+#[derive(Debug, Deserialize, Clone)]
+pub struct LoginRateLimitConfig {
+    /// Master switch for all login brute-force protection (per-IP token bucket
+    /// and failed-attempt lockouts).
+    #[serde(default = "default_login_rate_limit_enabled")]
+    pub enabled: bool,
+    /// Per-IP token bucket for POST /api/auth/login: maximum burst of attempts.
+    #[serde(default = "default_login_ip_burst")]
+    pub ip_burst: u32,
+    /// Per-IP token bucket: one attempt is replenished every N seconds.
+    #[serde(default = "default_login_ip_replenish_secs")]
+    pub ip_replenish_secs: u64,
+    /// Failed logins (any account) from one client IP inside `failure_window_secs`
+    /// before that IP is locked out. 0 disables the per-IP lockout.
+    #[serde(default = "default_login_ip_max_failures")]
+    pub ip_max_failures: u32,
+    /// Failed logins for one account (case-insensitive e-mail, any IP) inside
+    /// `failure_window_secs` before that account is locked out. 0 disables it.
+    #[serde(default = "default_login_account_max_failures")]
+    pub account_max_failures: u32,
+    /// Window in which failed attempts are counted.
+    #[serde(default = "default_login_failure_window_secs")]
+    pub failure_window_secs: u64,
+    /// Duration of the first lockout. Each consecutive lockout of the same key
+    /// doubles the duration, up to `max_lockout_secs`.
+    #[serde(default = "default_login_lockout_secs")]
+    pub lockout_secs: u64,
+    /// Upper bound for the exponential lockout back-off.
+    #[serde(default = "default_login_max_lockout_secs")]
+    pub max_lockout_secs: u64,
+    /// Client IPs/CIDRs that never receive a per-IP lockout (for example an
+    /// internal monitoring probe). Account lockouts still apply to them.
+    #[serde(default)]
+    pub exempt_networks: Vec<String>,
+    /// Memory cap for each tracking table (accounts and IPs).
+    #[serde(default = "default_login_max_tracked_keys")]
+    pub max_tracked_keys: usize,
+}
+
+impl Default for LoginRateLimitConfig {
+    fn default() -> Self {
+        Self {
+            enabled: default_login_rate_limit_enabled(),
+            ip_burst: default_login_ip_burst(),
+            ip_replenish_secs: default_login_ip_replenish_secs(),
+            ip_max_failures: default_login_ip_max_failures(),
+            account_max_failures: default_login_account_max_failures(),
+            failure_window_secs: default_login_failure_window_secs(),
+            lockout_secs: default_login_lockout_secs(),
+            max_lockout_secs: default_login_max_lockout_secs(),
+            exempt_networks: Vec::new(),
+            max_tracked_keys: default_login_max_tracked_keys(),
+        }
+    }
+}
+
+impl LoginRateLimitConfig {
+    pub fn parsed_exempt_networks(&self) -> Result<Vec<IpNet>, String> {
+        self.exempt_networks
+            .iter()
+            .map(|entry| {
+                parse_ip_or_network(entry).map_err(|e| {
+                    format!(
+                        "invalid login_rate_limit.exempt_networks entry '{}': {e}",
+                        entry.trim()
+                    )
+                })
+            })
+            .collect()
+    }
+
+    pub fn validate(&self) -> Result<(), String> {
+        if !self.enabled {
+            return Ok(());
+        }
+        if self.ip_burst == 0 || self.ip_burst > 1000 {
+            return Err("LOGIN_RATE_LIMIT__IP_BURST must be between 1 and 1000".to_string());
+        }
+        if self.ip_replenish_secs == 0 || self.ip_replenish_secs > 3600 {
+            return Err(
+                "LOGIN_RATE_LIMIT__IP_REPLENISH_SECS must be between 1 and 3600".to_string(),
+            );
+        }
+        if self.failure_window_secs == 0 || self.failure_window_secs > 86_400 {
+            return Err(
+                "LOGIN_RATE_LIMIT__FAILURE_WINDOW_SECS must be between 1 and 86400".to_string(),
+            );
+        }
+        if self.lockout_secs == 0 || self.lockout_secs > 86_400 {
+            return Err("LOGIN_RATE_LIMIT__LOCKOUT_SECS must be between 1 and 86400".to_string());
+        }
+        if self.max_lockout_secs < self.lockout_secs || self.max_lockout_secs > 7 * 86_400 {
+            return Err(
+                "LOGIN_RATE_LIMIT__MAX_LOCKOUT_SECS must be >= lockout_secs and <= 604800"
+                    .to_string(),
+            );
+        }
+        if self.max_tracked_keys < 100 || self.max_tracked_keys > 10_000_000 {
+            return Err(
+                "LOGIN_RATE_LIMIT__MAX_TRACKED_KEYS must be between 100 and 10000000".to_string(),
+            );
+        }
+        self.parsed_exempt_networks()?;
+        Ok(())
+    }
+}
+
+fn parse_ip_or_network(entry: &str) -> Result<IpNet, String> {
+    let trimmed = entry.trim();
+    if let Ok(network) = trimmed.parse::<IpNet>() {
+        return Ok(network);
+    }
+    let ip = trimmed.parse::<IpAddr>().map_err(|e| e.to_string())?;
+    Ok(match ip {
+        IpAddr::V4(value) => IpNet::V4(Ipv4Net::new(value, 32).expect("valid IPv4 prefix")),
+        IpAddr::V6(value) => IpNet::V6(Ipv6Net::new(value, 128).expect("valid IPv6 prefix")),
+    })
+}
+
 #[derive(Debug, Deserialize, Clone)]
 #[allow(dead_code)]
 pub struct AppConfig {
@@ -213,6 +332,26 @@ pub struct AppConfig {
     #[serde(default = "default_max_message_size_mb")]
     pub max_message_size_mb: usize,
 
+    /// Maximum number of requests that may hold attachment data in memory at
+    /// the same time while a message is sent, an IMAP draft snapshot is saved
+    /// or a message is attached. Peak RAM for these operations is roughly
+    /// `max_concurrent_message_builds` x a few times `max_message_size_mb`.
+    #[serde(default = "default_max_concurrent_message_builds")]
+    pub max_concurrent_message_builds: usize,
+
+    /// How long a request waits for a free slot before it is answered with 503.
+    #[serde(default = "default_message_build_wait_secs")]
+    pub message_build_wait_secs: u64,
+
+    /// How long a sent message is held back before actually reaching SMTP, so
+    /// the sender can cancel it ("Undo Send"). `0` disables the feature and
+    /// sends immediately, exactly as before this option existed. The built
+    /// message (including attachments) stays in memory for the whole window,
+    /// bounded by the same `max_concurrent_message_builds` slot it already
+    /// holds for an immediate send.
+    #[serde(default = "default_undo_send_window_secs")]
+    pub undo_send_window_secs: u64,
+
     #[serde(default = "default_data_dir")]
     pub data_dir: String,
 
@@ -264,6 +403,9 @@ pub struct AppConfig {
     #[serde(default)]
     pub diagnostics_endpoint: DiagnosticsEndpointConfig,
 
+    #[serde(default)]
+    pub login_rate_limit: LoginRateLimitConfig,
+
     #[serde(default = "default_session_timeout_hours")]
     pub session_timeout_hours: u64,
 
@@ -276,6 +418,11 @@ pub struct AppConfig {
     #[serde(default = "default_environment")]
     pub environment: String,
 
+    /// `Secure` attribute of session cookies: `auto` (only when the browser
+    /// reached RustBox over HTTPS), `always` or `never`.
+    #[serde(default = "default_cookie_secure")]
+    pub cookie_secure: String,
+
     #[serde(default = "default_theme")]
     pub default_theme: String,
 
@@ -401,6 +548,18 @@ fn default_max_message_size_mb() -> usize {
     50
 }
 
+fn default_max_concurrent_message_builds() -> usize {
+    4
+}
+
+fn default_message_build_wait_secs() -> u64 {
+    30
+}
+
+fn default_undo_send_window_secs() -> u64 {
+    8
+}
+
 fn default_data_dir() -> String {
     "/data".to_string()
 }
@@ -473,6 +632,42 @@ fn default_search_worker_max_attempts() -> u32 {
     12
 }
 
+fn default_login_rate_limit_enabled() -> bool {
+    true
+}
+
+fn default_login_ip_burst() -> u32 {
+    5
+}
+
+fn default_login_ip_replenish_secs() -> u64 {
+    12
+}
+
+fn default_login_ip_max_failures() -> u32 {
+    20
+}
+
+fn default_login_account_max_failures() -> u32 {
+    5
+}
+
+fn default_login_failure_window_secs() -> u64 {
+    900
+}
+
+fn default_login_lockout_secs() -> u64 {
+    300
+}
+
+fn default_login_max_lockout_secs() -> u64 {
+    3600
+}
+
+fn default_login_max_tracked_keys() -> usize {
+    100_000
+}
+
 fn default_log_level() -> String {
     "info".to_string()
 }
@@ -508,6 +703,10 @@ fn default_environment() -> String {
     "development".to_string()
 }
 
+fn default_cookie_secure() -> String {
+    "auto".to_string()
+}
+
 fn default_theme() -> String {
     "system".to_string()
 }
@@ -562,6 +761,9 @@ impl Default for AppConfig {
             tls_verify: None,
             max_attachment_size_mb: default_max_attachment_size_mb(),
             max_message_size_mb: default_max_message_size_mb(),
+            max_concurrent_message_builds: default_max_concurrent_message_builds(),
+            message_build_wait_secs: default_message_build_wait_secs(),
+            undo_send_window_secs: default_undo_send_window_secs(),
             data_dir: default_data_dir(),
             log_dir: None,
             log_level: default_log_level(),
@@ -579,10 +781,12 @@ impl Default for AppConfig {
             search: SearchConfig::default(),
             sync: SyncConfig::default(),
             diagnostics_endpoint: DiagnosticsEndpointConfig::default(),
+            login_rate_limit: LoginRateLimitConfig::default(),
             session_timeout_hours: default_session_timeout_hours(),
             remember_me_enabled: default_remember_me_enabled(),
             remember_me_days: default_remember_me_days(),
             environment: default_environment(),
+            cookie_secure: default_cookie_secure(),
             default_theme: default_theme(),
             default_interface_skin: default_interface_skin(),
             base_path: None,
@@ -834,6 +1038,15 @@ impl AppConfig {
         if self.max_attachment_size_mb > self.max_message_size_mb {
             return Err("MAX_ATTACHMENT_SIZE_MB cannot exceed MAX_MESSAGE_SIZE_MB".to_string());
         }
+        if self.max_concurrent_message_builds == 0 || self.max_concurrent_message_builds > 256 {
+            return Err("MAX_CONCURRENT_MESSAGE_BUILDS must be between 1 and 256".to_string());
+        }
+        if self.message_build_wait_secs == 0 || self.message_build_wait_secs > 300 {
+            return Err("MESSAGE_BUILD_WAIT_SECS must be between 1 and 300".to_string());
+        }
+        if self.undo_send_window_secs > 120 {
+            return Err("UNDO_SEND_WINDOW_SECS must be between 0 and 120".to_string());
+        }
         if !matches!(self.database_backend.as_str(), "sqlite" | "mysql" | "pgsql") {
             return Err("DATABASE_BACKEND must be one of: sqlite, mysql, pgsql".to_string());
         }
@@ -1174,6 +1387,13 @@ impl AppConfig {
             }
         }
         self.parsed_outgoing_headers()?;
+        self.login_rate_limit.validate()?;
+        if !matches!(
+            self.cookie_secure.trim().to_ascii_lowercase().as_str(),
+            "auto" | "always" | "never"
+        ) {
+            return Err("COOKIE_SECURE must be one of: auto, always, never".to_string());
+        }
         if self.pgp_network_timeout_secs == 0 || self.pgp_network_timeout_secs > 60 {
             return Err("PGP_NETWORK_TIMEOUT_SECS must be between 1 and 60".to_string());
         }
@@ -1211,6 +1431,9 @@ mod tests {
         assert!(config.tls_verify_for_host("mail.example.com"));
         assert_eq!(config.max_attachment_size_mb, 10);
         assert_eq!(config.max_message_size_mb, 50);
+        assert_eq!(config.max_concurrent_message_builds, 4);
+        assert_eq!(config.message_build_wait_secs, 30);
+        assert_eq!(config.undo_send_window_secs, 8);
         assert_eq!(config.data_dir, "/data");
         assert!(config.log_dir.is_none());
         assert_eq!(config.database_backend, "sqlite");
@@ -1553,4 +1776,128 @@ mod tests {
         let error = config.validate().unwrap_err();
         assert!(error.contains("shared mysql/pgsql application database"));
     }
+
+    #[test]
+    fn login_rate_limit_defaults_are_enabled_and_valid() {
+        let config: AppConfig = Figment::new().extract().expect("defaults should load");
+        let limit = &config.login_rate_limit;
+        assert!(limit.enabled);
+        assert_eq!(limit.ip_burst, 5);
+        assert_eq!(limit.ip_replenish_secs, 12);
+        assert_eq!(limit.ip_max_failures, 20);
+        assert_eq!(limit.account_max_failures, 5);
+        assert_eq!(limit.failure_window_secs, 900);
+        assert_eq!(limit.lockout_secs, 300);
+        assert_eq!(limit.max_lockout_secs, 3600);
+        assert!(limit.exempt_networks.is_empty());
+        assert!(limit.validate().is_ok());
+        assert_eq!(config.cookie_secure, "auto");
+    }
+
+    #[test]
+    fn message_build_limits_are_validated() {
+        let valid = AppConfig {
+            imap_host: Some("imap.example.com".to_string()),
+            ..AppConfig::default()
+        };
+        assert!(valid.validate().is_ok());
+        for builds in [0usize, 257] {
+            let config = AppConfig {
+                max_concurrent_message_builds: builds,
+                ..valid.clone()
+            };
+            assert!(
+                config
+                    .validate()
+                    .unwrap_err()
+                    .contains("MAX_CONCURRENT_MESSAGE_BUILDS")
+            );
+        }
+        for wait in [0u64, 301] {
+            let config = AppConfig {
+                message_build_wait_secs: wait,
+                ..valid.clone()
+            };
+            assert!(
+                config
+                    .validate()
+                    .unwrap_err()
+                    .contains("MESSAGE_BUILD_WAIT_SECS")
+            );
+        }
+    }
+
+    #[test]
+    fn undo_send_window_is_validated() {
+        let valid = AppConfig {
+            imap_host: Some("imap.example.com".to_string()),
+            ..AppConfig::default()
+        };
+        assert!(valid.validate().is_ok());
+        let disabled = AppConfig {
+            undo_send_window_secs: 0,
+            ..valid.clone()
+        };
+        assert!(disabled.validate().is_ok());
+        let too_long = AppConfig {
+            undo_send_window_secs: 121,
+            ..valid
+        };
+        assert!(
+            too_long
+                .validate()
+                .unwrap_err()
+                .contains("UNDO_SEND_WINDOW_SECS")
+        );
+    }
+
+    #[test]
+    fn invalid_cookie_secure_mode_is_rejected() {
+        let config = AppConfig {
+            imap_host: Some("imap.example.com".to_string()),
+            cookie_secure: "sometimes".to_string(),
+            ..AppConfig::default()
+        };
+        assert!(config.validate().unwrap_err().contains("COOKIE_SECURE"));
+    }
+
+    #[test]
+    fn login_rate_limit_is_read_from_nested_config() {
+        let config: AppConfig = Figment::new()
+            .merge(("login_rate_limit.account_max_failures", 3u32))
+            .merge(("login_rate_limit.lockout_secs", 60u64))
+            .merge((
+                "login_rate_limit.exempt_networks",
+                vec!["10.0.0.0/8", "192.0.2.7"],
+            ))
+            .extract()
+            .expect("nested login_rate_limit should load");
+        assert_eq!(config.login_rate_limit.account_max_failures, 3);
+        assert_eq!(config.login_rate_limit.lockout_secs, 60);
+        assert_eq!(
+            config
+                .login_rate_limit
+                .parsed_exempt_networks()
+                .unwrap()
+                .len(),
+            2
+        );
+    }
+
+    #[test]
+    fn invalid_login_rate_limit_is_rejected() {
+        let mut limit = LoginRateLimitConfig {
+            ip_burst: 0,
+            ..LoginRateLimitConfig::default()
+        };
+        assert!(limit.validate().is_err());
+        limit.ip_burst = 5;
+        limit.max_lockout_secs = limit.lockout_secs - 1;
+        assert!(limit.validate().is_err());
+        limit.max_lockout_secs = 3600;
+        limit.exempt_networks = vec!["not-an-ip".to_string()];
+        assert!(limit.validate().is_err());
+        limit.enabled = false;
+        assert!(limit.validate().is_ok());
+    }
 }

src/db/mod.rs

@@ -16,6 +16,7 @@ pub mod pool;
 pub mod response_templates;
 pub mod search_outbox;
 pub mod settings;
+pub mod snooze;
 pub mod special_folders;
 pub mod tags;
 pub mod trusted_senders;

src/db/pool.rs

@@ -21,20 +21,33 @@ const SQLITE_SCHEMA: &str = include_str!("../../migrations/sqlite/schema.sql");
 const MYSQL_SCHEMA: &str = include_str!("../../migrations/mysql/schema.sql");
 const PGSQL_SCHEMA: &str = include_str!("../../migrations/pgsql/schema.sql");
 
-const SQLITE_MIGRATIONS: &[(u32, &str)] = &[(
+const SQLITE_MIGRATIONS: &[(u32, &str)] = &[
+    (
         51,
         include_str!(
             "../../migrations/sqlite/V051__adaptive_email_colors_and_message_loading_mode.sql"
         ),
-)];
-const MYSQL_MIGRATIONS: &[(u32, &str)] = &[(
+    ),
+    (52, include_str!("../../migrations/sqlite/V052__snooze.sql")),
+];
+const MYSQL_MIGRATIONS: &[(u32, &str)] = &[
+    (
         51,
-    include_str!("../../migrations/mysql/V051__adaptive_email_colors_and_message_loading_mode.sql"),
-)];
-const PGSQL_MIGRATIONS: &[(u32, &str)] = &[(
+        include_str!(
+            "../../migrations/mysql/V051__adaptive_email_colors_and_message_loading_mode.sql"
+        ),
+    ),
+    (52, include_str!("../../migrations/mysql/V052__snooze.sql")),
+];
+const PGSQL_MIGRATIONS: &[(u32, &str)] = &[
+    (
         51,
-    include_str!("../../migrations/pgsql/V051__adaptive_email_colors_and_message_loading_mode.sql"),
-)];
+        include_str!(
+            "../../migrations/pgsql/V051__adaptive_email_colors_and_message_loading_mode.sql"
+        ),
+    ),
+    (52, include_str!("../../migrations/pgsql/V052__snooze.sql")),
+];
 
 const TENANT_TABLES: &[&str] = &[
     "blob_delete_outbox",
@@ -61,6 +74,7 @@ const TENANT_TABLES: &[&str] = &[
     "response_templates",
     "saved_searches",
     "search_outbox",
+    "snoozed_messages",
     "special_folders",
     "tags",
     "trusted_senders",
@@ -87,6 +101,7 @@ const IMPORT_TABLES: &[&str] = &[
     "messages",
     "tags",
     "message_tags",
+    "snoozed_messages",
     "notification_preferences",
     "pgp_keys",
     "pgp_preferences",
@@ -2648,7 +2663,7 @@ mod tests {
                 |row| row.get(0),
             )
             .unwrap();
-        assert_eq!(version, 51);
+        assert_eq!(version, 52);
 
         let adaptive: i64 = conn
             .query_row(

src/db/snooze.rs

@@ -0,0 +1,191 @@
+//! Snoozing a message hides it from its folder listing until a chosen wake
+//! time. This is purely local cache state: nothing is moved on the real IMAP
+//! server, so snoozing never risks the actual mailbox. The client is
+//! responsible for excluding a still-sleeping message from the folder it
+//! renders and for showing the "Snoozed" view built from [`list_snoozed`].
+
+use std::time::{SystemTime, UNIX_EPOCH};
+
+use crate::db::pool::{Connection, params};
+
+pub fn now_epoch() -> i64 {
+    SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .unwrap_or_default()
+        .as_secs()
+        .min(i64::MAX as u64) as i64
+}
+
+#[derive(Debug, Clone, serde::Serialize)]
+pub struct SnoozedMessage {
+    pub id: String,
+    pub message_uid: u32,
+    pub message_folder: String,
+    pub wake_at: i64,
+    pub subject: String,
+    pub from_name: String,
+    pub from_address: String,
+    pub snippet: String,
+}
+
+/// Snoozes `(folder, uid)` until `wake_at` (epoch seconds), replacing any
+/// existing snooze for the same message. Returns the new snooze id.
+pub fn snooze_message(
+    conn: &Connection,
+    folder: &str,
+    uid: u32,
+    wake_at: i64,
+) -> Result<String, String> {
+    if folder.trim().is_empty() {
+        return Err("folder must not be empty".to_string());
+    }
+    if wake_at <= now_epoch() {
+        return Err("snooze wake time must be in the future".to_string());
+    }
+    conn.execute(
+        crate::dbq!(db_snoozed_messages::Q_002),
+        params![uid, folder],
+    )
+    .map_err(|e| format!("failed to clear existing snooze: {e}"))?;
+    let id = uuid::Uuid::new_v4().to_string();
+    conn.execute(
+        crate::dbq!(db_snoozed_messages::Q_001),
+        params![&id, uid, folder, wake_at],
+    )
+    .map_err(|e| format!("failed to snooze message: {e}"))?;
+    Ok(id)
+}
+
+/// Removes any snooze on `(folder, uid)`. Returns whether a row was removed.
+pub fn unsnooze_message(conn: &Connection, folder: &str, uid: u32) -> Result<bool, String> {
+    let changed = conn
+        .execute(
+            crate::dbq!(db_snoozed_messages::Q_002),
+            params![uid, folder],
+        )
+        .map_err(|e| format!("failed to unsnooze message: {e}"))?;
+    Ok(changed > 0)
+}
+
+/// Every snoozed message (woken or not), joined with the cached message
+/// metadata needed to render the "Snoozed" view, ordered by wake time.
+pub fn list_snoozed(conn: &Connection) -> Result<Vec<SnoozedMessage>, String> {
+    let mut stmt = conn
+        .prepare(crate::dbq!(db_snoozed_messages::Q_003))
+        .map_err(|e| format!("failed to prepare snoozed-messages query: {e}"))?;
+    let rows = stmt
+        .query_map([], |row| {
+            Ok(SnoozedMessage {
+                id: row.get(0)?,
+                message_uid: row.get::<_, i64>(1)?.max(0) as u32,
+                message_folder: row.get(2)?,
+                wake_at: row.get(3)?,
+                subject: row.get::<_, Option<String>>(4)?.unwrap_or_default(),
+                from_name: row.get::<_, Option<String>>(5)?.unwrap_or_default(),
+                from_address: row.get::<_, Option<String>>(6)?.unwrap_or_default(),
+                snippet: row.get::<_, Option<String>>(7)?.unwrap_or_default(),
+            })
+        })
+        .map_err(|e| format!("failed to query snoozed messages: {e}"))?;
+    rows.map(|row| row.map_err(|e| format!("failed to read snoozed message row: {e}")))
+        .collect()
+}
+
+/// The UIDs in `folder` that are still asleep as of `now` (i.e. due to be
+/// hidden from that folder's listing right now). Cheap enough for the client
+/// to call once per folder open; no IMAP or background work is involved.
+pub fn list_sleeping_uids_in_folder(
+    conn: &Connection,
+    folder: &str,
+    now: i64,
+) -> Result<Vec<u32>, String> {
+    let mut stmt = conn
+        .prepare(crate::dbq!(db_snoozed_messages::Q_004))
+        .map_err(|e| format!("failed to prepare sleeping-uids query: {e}"))?;
+    let rows = stmt
+        .query_map(params![folder, now], |row| {
+            Ok(row.get::<_, i64>(0)?.max(0) as u32)
+        })
+        .map_err(|e| format!("failed to query sleeping uids: {e}"))?;
+    rows.map(|row| row.map_err(|e| format!("failed to read sleeping uid row: {e}")))
+        .collect()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::db::pool::open_test_db;
+
+    fn insert_cached_message(conn: &Connection, folder: &str, uid: u32, subject: &str) {
+        conn.execute(
+            "INSERT OR IGNORE INTO folders (name) VALUES (?1)",
+            params![folder],
+        )
+        .unwrap();
+        conn.execute(
+            "INSERT INTO messages (uid, folder, subject, date, size) VALUES (?1, ?2, ?3, '', 0)",
+            params![uid, folder, subject],
+        )
+        .unwrap();
+    }
+
+    #[test]
+    fn snoozing_rejects_a_wake_time_in_the_past() {
+        let conn = open_test_db();
+        let error = snooze_message(&conn, "INBOX", 1, now_epoch() - 10).unwrap_err();
+        assert!(error.contains("future"));
+    }
+
+    #[test]
+    fn re_snoozing_the_same_message_replaces_the_wake_time() {
+        let conn = open_test_db();
+        let future = now_epoch() + 3600;
+        let later = now_epoch() + 7200;
+        snooze_message(&conn, "INBOX", 42, future).unwrap();
+        snooze_message(&conn, "INBOX", 42, later).unwrap();
+        let snoozed = list_snoozed(&conn).unwrap();
+        assert_eq!(snoozed.len(), 1);
+        assert_eq!(snoozed[0].wake_at, later);
+    }
+
+    #[test]
+    fn unsnoozing_removes_the_entry() {
+        let conn = open_test_db();
+        snooze_message(&conn, "INBOX", 7, now_epoch() + 60).unwrap();
+        assert!(unsnooze_message(&conn, "INBOX", 7).unwrap());
+        assert!(list_snoozed(&conn).unwrap().is_empty());
+        assert!(!unsnooze_message(&conn, "INBOX", 7).unwrap());
+    }
+
+    #[test]
+    fn list_snoozed_carries_cached_message_metadata() {
+        let conn = open_test_db();
+        insert_cached_message(&conn, "INBOX", 11, "Quarterly report");
+        snooze_message(&conn, "INBOX", 11, now_epoch() + 60).unwrap();
+        let snoozed = list_snoozed(&conn).unwrap();
+        assert_eq!(snoozed.len(), 1);
+        assert_eq!(snoozed[0].subject, "Quarterly report");
+    }
+
+    #[test]
+    fn sleeping_uids_exclude_already_woken_snoozes() {
+        let conn = open_test_db();
+        let now = now_epoch();
+        snooze_message(&conn, "INBOX", 1, now + 60).unwrap();
+        snooze_message(&conn, "INBOX", 2, now + 120).unwrap();
+        let sleeping = list_sleeping_uids_in_folder(&conn, "INBOX", now).unwrap();
+        assert_eq!(sleeping.len(), 2);
+        let sleeping_later = list_sleeping_uids_in_folder(&conn, "INBOX", now + 90).unwrap();
+        assert_eq!(sleeping_later, vec![2]);
+    }
+
+    #[test]
+    fn sleeping_uids_are_scoped_to_their_folder() {
+        let conn = open_test_db();
+        let now = now_epoch();
+        snooze_message(&conn, "INBOX", 1, now + 60).unwrap();
+        snooze_message(&conn, "Archive", 2, now + 60).unwrap();
+        let sleeping = list_sleeping_uids_in_folder(&conn, "INBOX", now).unwrap();
+        assert_eq!(sleeping, vec![1]);
+    }
+}

src/main.rs

@@ -5,6 +5,7 @@ mod db;
 mod email_theme;
 mod error;
 mod imap;
+mod message_budget;
 mod pgp;
 mod queries;
 mod realtime;
@@ -15,6 +16,7 @@ mod sieve;
 mod smtp;
 mod storage;
 mod ui;
+mod undo_send;
 
 use std::fs::OpenOptions;
 use std::sync::{Arc, Mutex};

src/message_budget.rs

@@ -0,0 +1,185 @@
+//! Memory guards for assembling messages that carry attachments.
+//!
+//! Attachments are streamed to blob storage on upload, but sending a message or
+//! saving an IMAP draft snapshot has to load every attachment into memory, and
+//! the MIME builder then keeps several copies (raw bytes, base64 body, final
+//! RFC 5322 text, the copy appended to the Sent folder). Two guards keep that
+//! bounded:
+//!
+//! * [`ensure_attachments_fit`] rejects an attachment set that cannot fit
+//!   `max_message_size_mb` *before* any blob is read, using the sizes already
+//!   stored in the database (and while an upload is still streaming).
+//! * [`MessageBuildLimiter`] caps how many requests may hold attachment data in
+//!   memory at the same time (`max_concurrent_message_builds`). Excess requests
+//!   wait up to `message_build_wait_secs` and then get `503`.
+
+use std::sync::Arc;
+use std::time::Duration;
+
+use tokio::sync::{OwnedSemaphorePermit, Semaphore};
+
+use crate::db::drafts::DraftAttachment;
+use crate::error::AppError;
+
+/// Allowance for the MIME headers and boundary lines of one attachment part.
+const PER_PART_OVERHEAD_BYTES: u64 = 512;
+
+/// Size of `raw_bytes` of attachment data spread over `parts` MIME parts after
+/// base64 encoding (4 bytes per 3, plus a CRLF every 76 characters).
+pub fn encoded_size_estimate(raw_bytes: u64, parts: usize) -> u64 {
+    let base64 = raw_bytes.div_ceil(3).saturating_mul(4);
+    let line_breaks = base64.div_ceil(76).saturating_mul(2);
+    base64
+        .saturating_add(line_breaks)
+        .saturating_add((parts as u64).saturating_mul(PER_PART_OVERHEAD_BYTES))
+}
+
+/// Sum of the sizes recorded for stored draft attachments.
+pub fn draft_attachments_total(records: &[DraftAttachment]) -> u64 {
+    records
+        .iter()
+        .map(|record| u64::try_from(record.size).unwrap_or(0))
+        .sum()
+}
+
+fn mib(bytes: u64) -> f64 {
+    bytes as f64 / 1024.0 / 1024.0
+}
+
+/// Fails with `413` when `raw_bytes` of attachments (in `parts` parts) would
+/// exceed `limit_bytes` once MIME-encoded. A limit of 0 disables the check.
+pub fn ensure_attachments_fit(
+    limit_bytes: usize,
+    raw_bytes: u64,
+    parts: usize,
+) -> Result<(), AppError> {
+    if limit_bytes == 0 {
+        return Ok(());
+    }
+    let estimate = encoded_size_estimate(raw_bytes, parts);
+    if estimate > limit_bytes as u64 {
+        return Err(AppError::PayloadTooLarge(format!(
+            "Attachments total {:.2} MiB ({:.2} MiB after MIME encoding); the message size limit is {:.2} MiB",
+            mib(raw_bytes),
+            mib(estimate),
+            mib(limit_bytes as u64)
+        )));
+    }
+    Ok(())
+}
+
+/// Bounds the number of requests that hold attachment data in memory at once.
+#[derive(Debug)]
+pub struct MessageBuildLimiter {
+    semaphore: Arc<Semaphore>,
+    wait: Duration,
+}
+
+impl MessageBuildLimiter {
+    pub fn new(max_concurrent: usize, wait: Duration) -> Self {
+        Self {
+            semaphore: Arc::new(Semaphore::new(max_concurrent.max(1))),
+            wait,
+        }
+    }
+
+    /// Waits (first come, first served) for a free slot. Keep the returned
+    /// permit alive for as long as the attachment data is in memory.
+    pub async fn acquire(&self) -> Result<OwnedSemaphorePermit, AppError> {
+        match tokio::time::timeout(self.wait, self.semaphore.clone().acquire_owned()).await {
+            Ok(Ok(permit)) => Ok(permit),
+            Ok(Err(_closed)) => Err(AppError::InternalError(
+                "message build limiter is closed".to_string(),
+            )),
+            Err(_elapsed) => {
+                tracing::warn!(
+                    wait_secs = self.wait.as_secs_f32(),
+                    "too many messages with attachments are being assembled; request rejected"
+                );
+                Err(AppError::ServiceUnavailable(
+                    "The server is busy assembling other messages with attachments; try again in a moment"
+                        .to_string(),
+                ))
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn estimate_accounts_for_base64_line_breaks_and_part_overhead() {
+        // 57 raw bytes -> 76 base64 characters -> one CRLF -> +512 part overhead.
+        assert_eq!(encoded_size_estimate(57, 1), 76 + 2 + 512);
+        assert_eq!(encoded_size_estimate(0, 0), 0);
+        let raw = 9_000_000u64;
+        let estimate = encoded_size_estimate(raw, 1);
+        assert!(estimate > raw * 4 / 3);
+        assert!(estimate < raw * 4 / 3 + raw / 20);
+    }
+
+    #[test]
+    fn attachments_over_the_message_limit_are_rejected_before_loading() {
+        let limit = 10 * 1024 * 1024;
+        assert!(ensure_attachments_fit(limit, 7_000_000, 2).is_ok());
+        let error = ensure_attachments_fit(limit, 8_000_000, 2).unwrap_err();
+        assert!(matches!(error, AppError::PayloadTooLarge(_)));
+        assert!(
+            error
+                .to_string()
+                .contains("message size limit is 10.00 MiB")
+        );
+        // The same bytes split over many parts cost extra overhead.
+        assert!(ensure_attachments_fit(limit, 7_300_000, 1).is_ok());
+        assert!(ensure_attachments_fit(limit, 7_300_000, 5_000).is_err());
+        assert!(ensure_attachments_fit(0, u64::MAX, 1).is_ok());
+    }
+
+    #[test]
+    fn totals_ignore_invalid_negative_sizes() {
+        let record = |size: i64| DraftAttachment {
+            id: "a".to_string(),
+            draft_id: "d".to_string(),
+            filename: "f".to_string(),
+            content_type: "application/octet-stream".to_string(),
+            size,
+            storage_key: "k".to_string(),
+            checksum_sha256: None,
+            created_at: String::new(),
+        };
+        assert_eq!(
+            draft_attachments_total(&[record(10), record(-5), record(32)]),
+            42
+        );
+    }
+
+    #[tokio::test]
+    async fn limiter_queues_then_rejects_when_slots_stay_busy() {
+        let limiter = MessageBuildLimiter::new(1, Duration::from_millis(60));
+        let first = limiter.acquire().await.expect("first slot");
+
+        let error = limiter.acquire().await.unwrap_err();
+        assert!(matches!(error, AppError::ServiceUnavailable(_)));
+
+        drop(first);
+        let _second = limiter
+            .acquire()
+            .await
+            .expect("slot is available again after the permit is dropped");
+    }
+
+    #[tokio::test]
+    async fn limiter_hands_a_slot_to_a_waiting_request() {
+        let limiter = Arc::new(MessageBuildLimiter::new(1, Duration::from_secs(5)));
+        let first = limiter.acquire().await.unwrap();
+        let waiting = {
+            let limiter = limiter.clone();
+            tokio::spawn(async move { limiter.acquire().await.map(|_| ()) })
+        };
+        tokio::time::sleep(Duration::from_millis(30)).await;
+        drop(first);
+        assert!(waiting.await.unwrap().is_ok());
+    }
+}

src/queries/mysql/queries.rs

@@ -406,6 +406,18 @@ pub mod db_saved_searches {
     pub const Q_005: &str = "DELETE FROM saved_searches WHERE id=?";
 }
 
+pub mod db_snoozed_messages {
+    pub const Q_001: &str = "INSERT INTO snoozed_messages (id, message_uid, message_folder, wake_at) VALUES (?, ?, ?, ?)";
+    pub const Q_002: &str =
+        "DELETE FROM snoozed_messages WHERE message_uid = ? AND message_folder = ?";
+    pub const Q_003: &str =
+        "SELECT s.id, s.message_uid, s.message_folder, s.wake_at, m.subject, m.from_name, m.from_address, m.snippet
+             FROM snoozed_messages s
+             LEFT JOIN messages m ON m.uid = s.message_uid AND m.folder = s.message_folder
+             ORDER BY s.wake_at ASC";
+    pub const Q_004: &str = "SELECT message_uid FROM snoozed_messages WHERE message_folder = ? AND wake_at > ? ORDER BY wake_at ASC";
+}
+
 pub mod db_special_folders {
     pub const Q_001: &str = "SELECT folder_name FROM special_folders WHERE role = ?";
     pub const Q_002: &str = "SELECT EXISTS(SELECT 1 FROM folders WHERE name = ?)";

src/queries/pgsql/queries.rs

@@ -406,6 +406,18 @@ pub mod db_saved_searches {
     pub const Q_005: &str = "DELETE FROM saved_searches WHERE id=$1";
 }
 
+pub mod db_snoozed_messages {
+    pub const Q_001: &str = "INSERT INTO snoozed_messages (id, message_uid, message_folder, wake_at) VALUES ($1, $2, $3, $4)";
+    pub const Q_002: &str =
+        "DELETE FROM snoozed_messages WHERE message_uid = $1 AND message_folder = $2";
+    pub const Q_003: &str =
+        "SELECT s.id, s.message_uid, s.message_folder, s.wake_at, m.subject, m.from_name, m.from_address, m.snippet
+             FROM snoozed_messages s
+             LEFT JOIN messages m ON m.uid = s.message_uid AND m.folder = s.message_folder
+             ORDER BY s.wake_at ASC";
+    pub const Q_004: &str = "SELECT message_uid FROM snoozed_messages WHERE message_folder = $1 AND wake_at > $2 ORDER BY wake_at ASC";
+}
+
 pub mod db_special_folders {
     pub const Q_001: &str = "SELECT folder_name FROM special_folders WHERE role = $1";
     pub const Q_002: &str = "SELECT EXISTS(SELECT 1 FROM folders WHERE name = $1)";

src/queries/sqlite/queries.rs

@@ -403,6 +403,18 @@ pub mod db_saved_searches {
     pub const Q_005: &str = "DELETE FROM saved_searches WHERE id=?1";
 }
 
+pub mod db_snoozed_messages {
+    pub const Q_001: &str = "INSERT INTO snoozed_messages (id, message_uid, message_folder, wake_at) VALUES (?1, ?2, ?3, ?4)";
+    pub const Q_002: &str =
+        "DELETE FROM snoozed_messages WHERE message_uid = ?1 AND message_folder = ?2";
+    pub const Q_003: &str =
+        "SELECT s.id, s.message_uid, s.message_folder, s.wake_at, m.subject, m.from_name, m.from_address, m.snippet
+             FROM snoozed_messages s
+             LEFT JOIN messages m ON m.uid = s.message_uid AND m.folder = s.message_folder
+             ORDER BY s.wake_at ASC";
+    pub const Q_004: &str = "SELECT message_uid FROM snoozed_messages WHERE message_folder = ?1 AND wake_at > ?2 ORDER BY wake_at ASC";
+}
+
 pub mod db_special_folders {
     pub const Q_001: &str = "SELECT folder_name FROM special_folders WHERE role = ?1";
     pub const Q_002: &str = "SELECT EXISTS(SELECT 1 FROM folders WHERE name = ?1)";

src/routes/attachments.rs

@@ -13,6 +13,7 @@ use crate::config::AppConfig;
 use crate::db;
 use crate::error::AppError;
 use crate::imap::client::{ImapClient, ImapCredentials};
+use crate::message_budget::{MessageBuildLimiter, draft_attachments_total, ensure_attachments_fit};
 use crate::storage::{self, BlobStorage, attachment_key};
 
 #[derive(Debug, Serialize)]
@@ -56,6 +57,13 @@ pub async fn upload_attachment(
 
     let mut uploaded = Vec::new();
     let max_attachment_size = config.max_attachment_size_bytes();
+    // The whole draft has to fit into one message, so stop an upload as soon as
+    // the attachments already stored plus this request would exceed the limit.
+    let max_message_size = config.max_message_size_bytes();
+    let existing_attachments =
+        db::drafts::get_draft_attachments(&conn, &draft_id).map_err(AppError::InternalError)?;
+    let mut message_attachment_bytes = draft_attachments_total(&existing_attachments);
+    let mut message_attachment_parts = existing_attachments.len();
 
     while let Some(mut field) = multipart
         .next_field()
@@ -76,6 +84,7 @@ pub async fn upload_attachment(
             .map_err(|e| AppError::ServiceUnavailable(format!("Storage unavailable: {e}")))?;
         let mut size: usize = 0;
         let mut checksum = Sha256::new();
+        message_attachment_parts += 1;
 
         loop {
             let chunk = match field.chunk().await {
@@ -107,6 +116,19 @@ pub async fn upload_attachment(
                     filename, config.max_attachment_size_mb
                 )));
             }
+            if let Err(error) = ensure_attachments_fit(
+                max_message_size,
+                message_attachment_bytes.saturating_add(size as u64),
+                message_attachment_parts,
+            ) {
+                if writer.abort().await.is_err()
+                    && let Err(cleanup_error) =
+                        storage::enqueue_unreferenced_delete(&conn, storage.as_ref(), &key).await
+                {
+                    tracing::error!(error = %cleanup_error, storage_key = %key, "Failed to queue over-limit attachment cleanup");
+                }
+                return Err(error);
+            }
             checksum.update(&chunk);
             if let Err(e) = writer.write(chunk).await {
                 if writer.abort().await.is_err()
@@ -145,6 +167,7 @@ pub async fn upload_attachment(
             )));
         }
         let checksum = format!("{:x}", checksum.finalize());
+        message_attachment_bytes = message_attachment_bytes.saturating_add(size as u64);
         let size = size as i64;
         let attachment = db::drafts::NewDraftAttachment {
             id: &att_id,
@@ -187,6 +210,7 @@ pub async fn attach_message_source(
     Extension(config): Extension<Arc<AppConfig>>,
     Extension(storage): Extension<Arc<dyn BlobStorage>>,
     Extension(imap_client): Extension<Arc<dyn ImapClient>>,
+    Extension(build_limiter): Extension<Arc<MessageBuildLimiter>>,
     AxumPath(draft_id): AxumPath<String>,
     Json(req): Json<AttachMessageSourceRequest>,
 ) -> Result<Response, AppError> {
@@ -205,6 +229,9 @@ pub async fn attach_message_source(
         email: session.email.clone(),
         password: session.password.clone(),
     };
+    // The whole source message is fetched into memory: bound how many of these
+    // (and message builds) run at the same time.
+    let _build_permit = build_limiter.acquire().await?;
     let raw = imap_client
         .fetch_raw_message(&creds, &req.folder, req.uid)
         .await
@@ -232,6 +259,14 @@ pub async fn attach_message_source(
         .map_err(AppError::InternalError)?;
     }
 
+    let existing_attachments =
+        db::drafts::get_draft_attachments(&conn, &draft_id).map_err(AppError::InternalError)?;
+    ensure_attachments_fit(
+        config.max_message_size_bytes(),
+        draft_attachments_total(&existing_attachments).saturating_add(raw.len() as u64),
+        existing_attachments.len() + 1,
+    )?;
+
     let filename = format!("message-{}.eml", req.uid);
     let content_type = "message/rfc822".to_string();
     let att_id = uuid::Uuid::new_v4().to_string();

src/routes/auth.rs

@@ -1,12 +1,14 @@
+use std::net::{IpAddr, Ipv4Addr, SocketAddr};
 use std::sync::Arc;
 
-use axum::extract::Path;
+use axum::extract::{ConnectInfo, Path};
 use axum::http::StatusCode;
 use axum::response::{IntoResponse, Response};
 use axum::{Extension, Json};
 use serde::{Deserialize, Serialize};
 
 use crate::auth::imap_auth::{self, AuthResult};
+use crate::auth::login_guard::{LoginBlocked, LoginGuard};
 use crate::auth::session::{NewAccountSession, SessionState, SessionStore};
 use crate::auth::user_data;
 use crate::config::AppConfig;
@@ -150,9 +152,133 @@ fn extract_session_cookies(headers: &axum::http::HeaderMap) -> Vec<(String, Stri
     sessions
 }
 
+/// Client IP used for login throttling; honours `trusted_proxies` the same way
+/// as the per-IP token bucket and the security telemetry.
+fn login_client_ip(
+    config: &AppConfig,
+    extensions: &axum::http::Extensions,
+    headers: &axum::http::HeaderMap,
+) -> IpAddr {
+    crate::routes::system_diagnostics::effective_client_ip(config, headers, peer_ip(extensions))
+}
+
+fn peer_ip(extensions: &axum::http::Extensions) -> IpAddr {
+    extensions
+        .get::<ConnectInfo<SocketAddr>>()
+        .map(|info| info.0.ip())
+        .unwrap_or(IpAddr::V4(Ipv4Addr::LOCALHOST))
+}
+
+/// Whether issued/cleared session cookies carry the `Secure` attribute.
+///
+/// `cookie_secure = "auto"` (default) marks cookies `Secure` only when the
+/// browser actually reached RustBox over HTTPS, so plain-HTTP installations
+/// keep working: a `Secure` cookie sent over HTTP is discarded by browsers and
+/// the user could never stay logged in.
+pub(crate) fn cookie_secure(
+    config: &AppConfig,
+    extensions: &axum::http::Extensions,
+    headers: &axum::http::HeaderMap,
+) -> bool {
+    match config.cookie_secure.trim().to_ascii_lowercase().as_str() {
+        "always" => true,
+        "never" => false,
+        _ => request_is_https(config, extensions, headers),
+    }
+}
+
+/// RustBox itself serves plain HTTP, so HTTPS can only be terminated in front
+/// of it. A scheme reported by a trusted reverse proxy (`X-Forwarded-Proto`,
+/// `Forwarded: proto=`, `X-Forwarded-Ssl`) wins; otherwise the scheme of the
+/// browser-supplied `Origin`/`Referer` is used. A forged header can only change
+/// the cookies issued to the client that forged it.
+fn request_is_https(
+    config: &AppConfig,
+    extensions: &axum::http::Extensions,
+    headers: &axum::http::HeaderMap,
+) -> bool {
+    let peer = peer_ip(extensions);
+    let peer_is_trusted_proxy = config
+        .parsed_trusted_proxies()
+        .iter()
+        .any(|proxy| proxy.contains(&peer));
+    if peer_is_trusted_proxy && let Some(proto) = forwarded_proto(headers) {
+        return proto == "https";
+    }
+    header_url_is_https(headers, "origin") || header_url_is_https(headers, "referer")
+}
+
+fn forwarded_proto(headers: &axum::http::HeaderMap) -> Option<String> {
+    let header = |name: &str| headers.get(name).and_then(|value| value.to_str().ok());
+
+    if let Some(proto) = header("x-forwarded-proto")
+        .and_then(|value| value.split(',').next())
+        .map(str::trim)
+        .filter(|value| !value.is_empty())
+    {
+        return Some(proto.to_ascii_lowercase());
+    }
+    if let Some(forwarded) = header("forwarded") {
+        for element in forwarded.split(',') {
+            for pair in element.split(';') {
+                if let Some((key, value)) = pair.split_once('=')
+                    && key.trim().eq_ignore_ascii_case("proto")
+                {
+                    return Some(value.trim().trim_matches('"').to_ascii_lowercase());
+                }
+            }
+        }
+    }
+    if header("x-forwarded-ssl").is_some_and(|value| value.trim().eq_ignore_ascii_case("on")) {
+        return Some("https".to_string());
+    }
+    None
+}
+
+fn header_url_is_https(headers: &axum::http::HeaderMap, name: &str) -> bool {
+    headers
+        .get(name)
+        .and_then(|value| value.to_str().ok())
+        .and_then(|value| value.trim().get(..8))
+        .is_some_and(|prefix| prefix.eq_ignore_ascii_case("https://"))
+}
+
+fn too_many_login_attempts(blocked: LoginBlocked) -> Response {
+    let retry_after = blocked.retry_after_secs();
+    (
+        StatusCode::TOO_MANY_REQUESTS,
+        [
+            ("content-type", "application/json".to_string()),
+            ("retry-after", retry_after.to_string()),
+        ],
+        serde_json::json!({
+            "error": {
+                "code": "TOO_MANY_LOGIN_ATTEMPTS",
+                "message": format!(
+                    "Too many failed login attempts. Try again in {}.",
+                    human_wait(retry_after)
+                ),
+                "status": 429,
+                "retryAfterSecs": retry_after
+            }
+        })
+        .to_string(),
+    )
+        .into_response()
+}
+
+fn human_wait(secs: u64) -> String {
+    if secs < 60 {
+        format!("{secs} s")
+    } else {
+        format!("{} min", secs.div_ceil(60))
+    }
+}
+
 pub async fn login(
     Extension(store): Extension<Arc<SessionStore>>,
     Extension(config): Extension<Arc<AppConfig>>,
+    extensions: axum::http::Extensions,
     headers: axum::http::HeaderMap,
     Json(body): Json<LoginRequest>,
 ) -> Response {
@@ -192,6 +318,20 @@ pub async fn login(
             .into_response();
     };
 
+    let login_guard = extensions.get::<Arc<LoginGuard>>().cloned();
+    let client_ip = login_client_ip(&config, &extensions, &headers);
+    if let Some(guard) = login_guard.as_deref()
+        && let Err(blocked) = guard.check(&body.email, client_ip)
+    {
+        tracing::warn!(
+            source_ip = %client_ip,
+            scope = blocked.scope.as_str(),
+            retry_after_secs = blocked.retry_after_secs(),
+            "login refused: brute-force lockout active"
+        );
+        return too_many_login_attempts(blocked);
+    }
+
     let smtp_host = config
         .smtp_host
         .clone()
@@ -214,6 +354,23 @@ pub async fn login(
     )
     .await;
 
+    if let Some(guard) = login_guard.as_deref() {
+        match &result {
+            AuthResult::Success => guard.record_success(&body.email),
+            AuthResult::InvalidCredentials => {
+                if let Some(locked) = guard.record_failure(&body.email, client_ip) {
+                    tracing::warn!(
+                        source_ip = %client_ip,
+                        scope = locked.scope.as_str(),
+                        lockout_secs = locked.retry_after_secs(),
+                        "login brute-force lockout triggered"
+                    );
+                }
+            }
+            AuthResult::ServerUnreachable(_) => {}
+        }
+    }
+
     match result {
         AuthResult::Success => {
             let provided_browser_id = body
@@ -366,7 +523,7 @@ pub async fn login(
             store.set_user_agent_shared(&account_id, user_agent).await;
 
             let max_age = session_hours * 3600;
-            let secure = config.environment != "development";
+            let secure = cookie_secure(&config, &extensions, &headers);
             let same_site = same_site_policy(&config);
             let path = cookie_path(&config);
             let browser_cookie_header =
@@ -439,9 +596,10 @@ pub async fn get_session(Extension(session): Extension<SessionState>) -> Respons
 pub async fn list_accounts(
     Extension(store): Extension<Arc<SessionStore>>,
     Extension(config): Extension<Arc<AppConfig>>,
+    extensions: axum::http::Extensions,
     headers: axum::http::HeaderMap,
 ) -> Response {
-    let secure = config.environment != "development";
+    let secure = cookie_secure(&config, &extensions, &headers);
     let same_site = same_site_policy(&config);
 
     let browser_id = extract_browser_id(&headers);
@@ -570,6 +728,7 @@ pub async fn remove_account(
     Extension(store): Extension<Arc<SessionStore>>,
     Extension(config): Extension<Arc<AppConfig>>,
     Path(account_id): Path<String>,
+    extensions: axum::http::Extensions,
     headers: axum::http::HeaderMap,
 ) -> Response {
     let browser_id = extract_browser_id(&headers);
@@ -611,7 +770,7 @@ pub async fn remove_account(
 
     store.remove_account_shared(&account_id).await;
 
-    let secure = config.environment != "development";
+    let secure = cookie_secure(&config, &extensions, &headers);
     let same_site = same_site_policy(&config);
     let cookie = clearing_account_cookie(&account_id, secure, same_site, cookie_path(&config));
 
@@ -764,13 +923,14 @@ pub async fn revoke_other_sessions(
 pub async fn logout(
     Extension(store): Extension<Arc<SessionStore>>,
     Extension(config): Extension<Arc<AppConfig>>,
+    extensions: axum::http::Extensions,
     headers: axum::http::HeaderMap,
 ) -> Response {
     let browser_id = extract_browser_id(&headers);
 
     let mut cookies_to_clear: Vec<String> = Vec::new();
 
-    let secure = config.environment != "development";
+    let secure = cookie_secure(&config, &extensions, &headers);
     let same_site = same_site_policy(&config);
 
     if let Some(ref browser_id) = browser_id {
@@ -947,6 +1107,7 @@ mod tests {
         let first = login(
             Extension(store.clone()),
             Extension(config.clone()),
+            axum::http::Extensions::new(),
             axum::http::HeaderMap::new(),
             Json(request("first@example.com")),
         )
@@ -968,6 +1129,7 @@ mod tests {
         let second = login(
             Extension(store.clone()),
             Extension(config.clone()),
+            axum::http::Extensions::new(),
             headers.clone(),
             Json(request("second@example.com")),
         )
@@ -995,6 +1157,7 @@ mod tests {
         let duplicate = login(
             Extension(store.clone()),
             Extension(config),
+            axum::http::Extensions::new(),
             headers,
             Json(request("second@example.com")),
         )
@@ -1004,6 +1167,190 @@ mod tests {
         imap.await.unwrap();
     }
 
+    #[tokio::test]
+    async fn repeated_failed_logins_lock_the_account_before_contacting_imap() {
+        use std::sync::atomic::{AtomicUsize, Ordering};
+        use tokio::io::{AsyncBufReadExt, AsyncWriteExt, BufReader};
+
+        let listener = tokio::net::TcpListener::bind("127.0.0.1:0").await.unwrap();
+        let port = listener.local_addr().unwrap().port();
+        let connections = Arc::new(AtomicUsize::new(0));
+        let seen = connections.clone();
+        let imap = tokio::spawn(async move {
+            loop {
+                let Ok((stream, _)) = listener.accept().await else {
+                    break;
+                };
+                seen.fetch_add(1, Ordering::SeqCst);
+                let mut stream = BufReader::new(stream);
+                stream
+                    .get_mut()
+                    .write_all(b"* OK test IMAP ready\r\n")
+                    .await
+                    .unwrap();
+                let mut command = String::new();
+                stream.read_line(&mut command).await.unwrap();
+                let tag = command
+                    .split_whitespace()
+                    .next()
+                    .unwrap_or("A1")
+                    .to_string();
+                let response = format!("{tag} NO [AUTHENTICATIONFAILED] Invalid credentials\r\n");
+                let _ = stream.get_mut().write_all(response.as_bytes()).await;
+            }
+        });
+
+        let data_dir = tempfile::tempdir().unwrap();
+        let mut config = test_config("development", None);
+        config.data_dir = data_dir.path().to_str().unwrap().to_string();
+        config.imap_host = Some("127.0.0.1".to_string());
+        config.imap_port = port;
+        config.tls_enabled = false;
+        config.login_rate_limit.account_max_failures = 2;
+        config.login_rate_limit.lockout_secs = 120;
+        let guard = Arc::new(LoginGuard::from_config(&config.login_rate_limit));
+        let config = Arc::new(config);
+        let store = Arc::new(SessionStore::new(std::time::Duration::from_secs(3600)));
+
+        let attempt = |email: &'static str| {
+            let mut extensions = axum::http::Extensions::new();
+            extensions.insert(guard.clone());
+            extensions.insert(ConnectInfo::<SocketAddr>(
+                "198.51.100.7:50000".parse().unwrap(),
+            ));
+            login(
+                Extension(store.clone()),
+                Extension(config.clone()),
+                extensions,
+                axum::http::HeaderMap::new(),
+                Json(LoginRequest {
+                    email: email.to_string(),
+                    password: "wrong".to_string(),
+                    remember: false,
+                    browser_id: None,
+                }),
+            )
+        };
+
+        assert_eq!(
+            attempt("victim@example.com").await.status(),
+            StatusCode::UNAUTHORIZED
+        );
+        assert_eq!(
+            attempt("Victim@Example.com").await.status(),
+            StatusCode::UNAUTHORIZED
+        );
+
+        let locked = attempt("victim@example.com").await;
+        assert_eq!(locked.status(), StatusCode::TOO_MANY_REQUESTS);
+        let retry_after: u64 = locked
+            .headers()
+            .get("retry-after")
+            .unwrap()
+            .to_str()
+            .unwrap()
+            .parse()
+            .unwrap();
+        assert!((1..=120).contains(&retry_after));
+        assert_eq!(connections.load(Ordering::SeqCst), 2);
+
+        // Another mailbox from the same IP is still allowed to try.
+        assert_eq!(
+            attempt("other@example.com").await.status(),
+            StatusCode::UNAUTHORIZED
+        );
+        assert_eq!(connections.load(Ordering::SeqCst), 3);
+        imap.abort();
+    }
+
+    fn request_parts(
+        peer: &str,
+        headers: &[(&'static str, &'static str)],
+    ) -> (axum::http::Extensions, axum::http::HeaderMap) {
+        let mut extensions = axum::http::Extensions::new();
+        extensions.insert(ConnectInfo::<SocketAddr>(peer.parse().unwrap()));
+        let mut map = axum::http::HeaderMap::new();
+        for &(name, value) in headers {
+            map.append(name, axum::http::HeaderValue::from_static(value));
+        }
+        (extensions, map)
+    }
+
+    fn secure_for(
+        config: &AppConfig,
+        peer: &str,
+        headers: &[(&'static str, &'static str)],
+    ) -> bool {
+        let (extensions, headers) = request_parts(peer, headers);
+        cookie_secure(config, &extensions, &headers)
+    }
+
+    #[test]
+    fn auto_cookie_secure_follows_the_real_request_scheme() {
+        let mut config = test_config("production", None);
+        config.trusted_proxies = Some("127.0.0.1,10.0.0.0/8".to_string());
+        let client = "192.0.2.10:5000";
+        let proxy = "10.0.0.2:5000";
+
+        // Plain HTTP install, even in production: no Secure flag, login keeps working.
+        assert!(!secure_for(&config, client, &[]));
+        assert!(!secure_for(
+            &config,
+            client,
+            &[("origin", "http://mail.example.com")]
+        ));
+        // Browser on HTTPS (TLS terminated in front of RustBox).
+        assert!(secure_for(
+            &config,
+            client,
+            &[("origin", "https://mail.example.com")]
+        ));
+        assert!(secure_for(
+            &config,
+            "127.0.0.1:5000",
+            &[("referer", "HTTPS://mail.example.com/inbox")]
+        ));
+        // Trusted reverse proxy reports the scheme explicitly and wins.
+        assert!(secure_for(
+            &config,
+            proxy,
+            &[("x-forwarded-proto", "https")]
+        ));
+        assert!(secure_for(
+            &config,
+            proxy,
+            &[("forwarded", "for=192.0.2.1;proto=https")]
+        ));
+        assert!(secure_for(&config, proxy, &[("x-forwarded-ssl", "on")]));
+        assert!(!secure_for(
+            &config,
+            proxy,
+            &[
+                ("x-forwarded-proto", "http"),
+                ("origin", "https://mail.example.com")
+            ]
+        ));
+        // Untrusted peers cannot assert the scheme through proxy headers.
+        assert!(!secure_for(
+            &config,
+            client,
+            &[("x-forwarded-proto", "https")]
+        ));
+    }
+
+    #[test]
+    fn cookie_secure_can_be_forced_from_config() {
+        let (extensions, headers) = request_parts("192.0.2.10:5000", &[]);
+        let mut config = test_config("development", None);
+        config.cookie_secure = "always".to_string();
+        assert!(cookie_secure(&config, &extensions, &headers));
+
+        let (extensions, headers) =
+            request_parts("192.0.2.10:5000", &[("origin", "https://mail.example.com")]);
+        config.cookie_secure = "never".to_string();
+        assert!(!cookie_secure(&config, &extensions, &headers));
+    }
+
     #[test]
     fn issued_and_clearing_cookies_use_the_normalized_base_path() {
         for (base_path, expected_path) in [

src/routes/drafts.rs

@@ -11,6 +11,7 @@ use crate::config::AppConfig;
 use crate::db;
 use crate::error::AppError;
 use crate::imap::client::{ImapClient, ImapCredentials};
+use crate::message_budget::{MessageBuildLimiter, draft_attachments_total, ensure_attachments_fit};
 use crate::smtp::client::AttachmentData;
 use crate::storage::{self, BlobStorage};
 
@@ -240,6 +241,7 @@ pub async fn upsert_draft_handler(
     Extension(config): Extension<Arc<AppConfig>>,
     Extension(imap_client): Extension<Arc<dyn ImapClient>>,
     Extension(storage): Extension<Arc<dyn BlobStorage>>,
+    Extension(build_limiter): Extension<Arc<MessageBuildLimiter>>,
     Json(req): Json<UpsertDraftRequest>,
 ) -> Result<Response, AppError> {
     db::drafts::validate_draft_id(&req.id).map_err(AppError::BadRequest)?;
@@ -306,7 +308,23 @@ pub async fn upsert_draft_handler(
             resolve_drafts_folder(&conn, &config).map_err(AppError::InternalError)?;
         tracing::debug!(folder = %drafts_folder, draft_id = %req.id, "Resolved IMAP drafts folder");
         let previous = db::drafts::get_draft(&conn, &req.id).map_err(AppError::InternalError)?;
-        let mut snapshot_attachments = load_snapshot_attachments(&conn, &req.id, storage.as_ref())
+        // Check the stored sizes first, then bound how many snapshots hold
+        // attachment data in RAM at once (released when this block ends).
+        let snapshot_records =
+            db::drafts::get_draft_attachments(&conn, &req.id).map_err(AppError::InternalError)?;
+        ensure_attachments_fit(
+            config.max_message_size_bytes(),
+            draft_attachments_total(&snapshot_records),
+            snapshot_records.len(),
+        )?;
+        let loads_attachment_data = !snapshot_records.is_empty()
+            || (req.imap_source.is_some() && !req.imap_attachments.is_empty());
+        let _build_permit = if loads_attachment_data {
+            Some(build_limiter.acquire().await?)
+        } else {
+            None
+        };
+        let mut snapshot_attachments = read_snapshot_attachments(storage.as_ref(), snapshot_records)
             .await
             .map_err(|e| {
                 tracing::warn!(error = %e, draft_id = %req.id, "Failed to load attachments for IMAP draft snapshot");
@@ -322,6 +340,15 @@ pub async fn upsert_draft_handler(
             .await?;
             snapshot_attachments.append(&mut remote_attachments);
         }
+        let snapshot_bytes: u64 = snapshot_attachments
+            .iter()
+            .map(|attachment| attachment.data.len() as u64)
+            .sum();
+        ensure_attachments_fit(
+            config.max_message_size_bytes(),
+            snapshot_bytes,
+            snapshot_attachments.len(),
+        )?;
         let selected_identity = if let Some(identity_id) = req.from_identity_id {
             Some(
                 db::identities::get_identity(&conn, identity_id)
@@ -699,12 +726,10 @@ async fn delete_imap_draft_source(
     Ok(true)
 }
 
-async fn load_snapshot_attachments(
-    conn: &crate::db::pool::Connection,
-    draft_id: &str,
+async fn read_snapshot_attachments(
     storage: &dyn BlobStorage,
+    records: Vec<db::drafts::DraftAttachment>,
 ) -> Result<Vec<AttachmentData>, String> {
-    let records = db::drafts::get_draft_attachments(conn, draft_id)?;
     let mut attachments = Vec::with_capacity(records.len());
     for record in records {
         let data = storage::read_all(storage, &record.storage_key)

src/routes/messages/mod.rs

@@ -1830,6 +1830,85 @@ pub async fn delete_message_handler(
     Ok(Json(serde_json::json!({ "status": "ok" })).into_response())
 }
 
+/// Snoozing is local cache state only: nothing moves on the real IMAP server.
+/// `wake_at` and `snooze_for_secs` are mutually exclusive ways to say when
+/// the message should reappear; the client is responsible for hiding a
+/// still-sleeping message from the folder it renders (see
+/// [`list_sleeping_uids`]) and for showing it again once `wake_at` passes.
+pub async fn snooze_message_handler(
+    Extension(session): Extension<SessionState>,
+    Extension(config): Extension<Arc<AppConfig>>,
+    Path((folder, uid)): Path<(String, u32)>,
+    Json(body): Json<SnoozeMessageRequest>,
+) -> Result<Response, AppError> {
+    let wake_at = match (body.wake_at, body.snooze_for_secs) {
+        (Some(_), Some(_)) => {
+            return Err(AppError::BadRequest(
+                "Specify either wake_at or snooze_for_secs, not both".to_string(),
+            ));
+        }
+        (Some(wake_at), None) => wake_at,
+        (None, Some(secs)) => {
+            if secs <= 0 {
+                return Err(AppError::BadRequest(
+                    "snooze_for_secs must be positive".to_string(),
+                ));
+            }
+            db::snooze::now_epoch().saturating_add(secs)
+        }
+        (None, None) => {
+            return Err(AppError::BadRequest(
+                "Specify wake_at or snooze_for_secs".to_string(),
+            ));
+        }
+    };
+
+    let conn = db::pool::open_user_db(&config.data_dir, &session.user_hash)
+        .map_err(|e| AppError::InternalError(format!("Database error: {e}")))?;
+    let id =
+        db::snooze::snooze_message(&conn, &folder, uid, wake_at).map_err(AppError::BadRequest)?;
+
+    Ok(Json(serde_json::json!({ "status": "ok", "id": id, "wake_at": wake_at })).into_response())
+}
+
+pub async fn unsnooze_message_handler(
+    Extension(session): Extension<SessionState>,
+    Extension(config): Extension<Arc<AppConfig>>,
+    Path((folder, uid)): Path<(String, u32)>,
+) -> Result<Response, AppError> {
+    let conn = db::pool::open_user_db(&config.data_dir, &session.user_hash)
+        .map_err(|e| AppError::InternalError(format!("Database error: {e}")))?;
+    db::snooze::unsnooze_message(&conn, &folder, uid).map_err(AppError::InternalError)?;
+    Ok(Json(serde_json::json!({ "status": "ok" })).into_response())
+}
+
+/// All snoozed messages (woken or not), for the "Snoozed" view.
+pub async fn list_snoozed_handler(
+    Extension(session): Extension<SessionState>,
+    Extension(config): Extension<Arc<AppConfig>>,
+) -> Result<Response, AppError> {
+    let conn = db::pool::open_user_db(&config.data_dir, &session.user_hash)
+        .map_err(|e| AppError::InternalError(format!("Database error: {e}")))?;
+    let snoozed = db::snooze::list_snoozed(&conn).map_err(AppError::InternalError)?;
+    Ok(Json(serde_json::json!({ "messages": snoozed })).into_response())
+}
+
+/// The UIDs in `folder` that are still snoozed as of now, so the client can
+/// hide those rows from the folder it is rendering. No IMAP or background
+/// work is involved; a message simply stops being returned here once its
+/// wake time passes.
+pub async fn list_sleeping_uids(
+    Extension(session): Extension<SessionState>,
+    Extension(config): Extension<Arc<AppConfig>>,
+    Path(folder): Path<String>,
+) -> Result<Response, AppError> {
+    let conn = db::pool::open_user_db(&config.data_dir, &session.user_hash)
+        .map_err(|e| AppError::InternalError(format!("Database error: {e}")))?;
+    let uids = db::snooze::list_sleeping_uids_in_folder(&conn, &folder, db::snooze::now_epoch())
+        .map_err(AppError::InternalError)?;
+    Ok(Json(serde_json::json!({ "uids": uids })).into_response())
+}
+
 #[cfg(test)]
 mod sync_tests {
     use super::*;

src/routes/messages/types.rs

@@ -42,6 +42,16 @@ pub(crate) struct CopyMessageRequest {
     pub(crate) uid: u32,
 }
 
+/// Either an absolute Unix epoch second, or a number of seconds from now.
+/// Exactly one must be set.
+#[derive(Deserialize)]
+pub(crate) struct SnoozeMessageRequest {
+    #[serde(default)]
+    pub(crate) wake_at: Option<i64>,
+    #[serde(default)]
+    pub(crate) snooze_for_secs: Option<i64>,
+}
+
 #[derive(Serialize)]
 pub(crate) struct ListMessagesResponse {
     pub(crate) messages: Vec<MessageSummary>,

src/routes/mod.rs

@@ -45,10 +45,12 @@ use tower_governor::key_extractor::KeyExtractor;
 use tower_http::trace::TraceLayer;
 
 use crate::auth::csrf::csrf_protection;
+use crate::auth::login_guard::LoginGuard;
 use crate::auth::middleware::auth_guard;
 use crate::auth::session::SessionStore;
 use crate::config::{AppConfig, TrustedProxy};
 use crate::imap::client::ImapClient;
+use crate::message_budget::MessageBuildLimiter;
 use crate::realtime::events::EventBus;
 use crate::realtime::idle::IdleManager;
 use crate::smtp::client::SmtpClient;
@@ -230,20 +232,38 @@ pub fn create_router_with_storage(config: Arc<AppConfig>, services: RouterServic
     } = services;
     let system_diagnostics_telemetry =
         Arc::new(system_diagnostics::SystemDiagnosticsTelemetry::new());
+    let build_limiter = Arc::new(MessageBuildLimiter::new(
+        config.max_concurrent_message_builds,
+        Duration::from_secs(config.message_build_wait_secs),
+    ));
+    let undo_send_registry = Arc::new(crate::undo_send::UndoSendRegistry::new());
+    let login_rate_limit = &config.login_rate_limit;
+    let login_guard = Arc::new(LoginGuard::from_config(login_rate_limit));
+
+    // Only the credential-checking endpoint is throttled; the public policy GET
+    // used by the login form must not consume the per-IP login budget.
+    let login_route = Router::new().route("/login", post(auth::login));
+    let login_route = if login_rate_limit.enabled {
         let governor_conf = GovernorConfigBuilder::default()
             .key_extractor(ProxyAwareIpExtractor {
                 trusted_proxies: config.parsed_trusted_proxies(),
             })
-        .period(Duration::from_secs(12))
-        .burst_size(5)
+            .period(Duration::from_secs(
+                login_rate_limit.ip_replenish_secs.max(1),
+            ))
+            .burst_size(login_rate_limit.ip_burst.max(1))
             .finish()
             .expect("valid governor config");
+        login_route.layer(GovernorLayer::new(governor_conf))
+    } else {
+        tracing::warn!("login_rate_limit.enabled=false: login brute-force protection is disabled");
+        login_route
+    };
 
     let public_auth = Router::new()
-        .route("/login", post(auth::login))
         .route("/policy", get(auth::auth_policy))
-        .layer(middleware::from_fn(csrf_protection))
-        .layer(GovernorLayer::new(governor_conf));
+        .merge(login_route)
+        .layer(middleware::from_fn(csrf_protection));
 
     let browser_routes = Router::new()
         .route("/accounts", get(auth::list_accounts))
@@ -293,6 +313,10 @@ pub fn create_router_with_storage(config: Arc<AppConfig>, services: RouterServic
             post(messages::import_eml).layer(DefaultBodyLimit::max(52 * 1024 * 1024)),
         )
         .route("/folders/{folder}/messages", get(messages::list_messages))
+        .route(
+            "/folders/{name}/snoozed-uids",
+            get(messages::list_sleeping_uids),
+        )
         .route(
             "/messages/{folder}/{uid}",
             get(messages::get_message).delete(messages::delete_message_handler),
@@ -301,6 +325,11 @@ pub fn create_router_with_storage(config: Arc<AppConfig>, services: RouterServic
             "/messages/{folder}/{uid}/flags",
             patch(messages::update_flags),
         )
+        .route(
+            "/messages/{folder}/{uid}/snooze",
+            post(messages::snooze_message_handler).delete(messages::unsnooze_message_handler),
+        )
+        .route("/messages/snoozed", get(messages::list_snoozed_handler))
         .route(
             "/messages/{folder}/{uid}/attachments/{attachment_id}",
             get(messages::download_attachment),
@@ -316,6 +345,10 @@ pub fn create_router_with_storage(config: Arc<AppConfig>, services: RouterServic
         .route("/messages/move", post(messages::move_message_handler))
         .route("/messages/copy", post(messages::copy_message_handler))
         .route("/messages/send", post(send::send_message_handler))
+        .route(
+            "/messages/send/{pending_send_id}",
+            get(send::pending_send_status).delete(send::cancel_pending_send),
+        )
         .route(
             "/messages/{folder}/{uid}/unsubscribe",
             post(unsubscribe::unsubscribe_message),
@@ -658,6 +691,9 @@ pub fn create_router_with_storage(config: Arc<AppConfig>, services: RouterServic
         .layer(Extension(storage))
         .layer(Extension(imap_client))
         .layer(Extension(store))
+        .layer(Extension(login_guard))
+        .layer(Extension(build_limiter))
+        .layer(Extension(undo_send_registry))
         .layer(Extension(config.clone()))
         .layer(TraceLayer::new_for_http());
 

src/routes/send.rs

@@ -1,5 +1,7 @@
 use std::sync::Arc;
+use std::time::Duration;
 
+use axum::extract::Path;
 use axum::response::{IntoResponse, Response};
 use axum::{Extension, Json};
 use base64::Engine as _;
@@ -11,10 +13,12 @@ use crate::config::AppConfig;
 use crate::db;
 use crate::error::AppError;
 use crate::imap::client::{ImapClient, ImapCredentials};
+use crate::message_budget::{MessageBuildLimiter, draft_attachments_total, ensure_attachments_fit};
 use crate::routes::drafts::{ImapDraftAttachmentRef, ImapDraftSource};
 use crate::smtp::client::{AttachmentData, SendableMessage, SmtpClient, SmtpCredentials};
 use crate::smtp::types::{PgpMode, PgpSendConfig};
 use crate::storage::{self, BlobStorage};
+use crate::undo_send::{PendingOutcome, UndoSendRegistry};
 
 #[derive(Deserialize)]
 pub struct SendRequest {
@@ -251,14 +255,25 @@ fn validate_mailbox(label: &str, value: &str) -> Result<(), AppError> {
 pub struct SendResponse {
     pub status: String,
     pub message_id: String,
+    /// Set only when the message was staged under "Undo Send" instead of
+    /// being dispatched immediately. Cancel it with
+    /// `DELETE /messages/send/{pending_send_id}` or poll
+    /// `GET /messages/send/{pending_send_id}` for the final result.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub pending_send_id: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub undo_window_secs: Option<u64>,
 }
 
+#[allow(clippy::too_many_arguments)]
 pub async fn send_message_handler(
     Extension(session): Extension<SessionState>,
     Extension(config): Extension<Arc<AppConfig>>,
     Extension(smtp_client): Extension<Arc<dyn SmtpClient>>,
     Extension(imap_client): Extension<Arc<dyn ImapClient>>,
     Extension(storage): Extension<Arc<dyn BlobStorage>>,
+    Extension(build_limiter): Extension<Arc<MessageBuildLimiter>>,
+    Extension(undo_registry): Extension<Arc<UndoSendRegistry>>,
     Json(req): Json<SendRequest>,
 ) -> Result<Response, AppError> {
     let imap_source = req.imap_source.clone();
@@ -443,17 +458,22 @@ pub async fn send_message_handler(
         validate_mailbox("read receipt", &receipt_address)?;
     }
 
-    let mut attachments = if let Some(ref draft_id) = req.draft_id {
-        load_draft_attachments(
-            &config.data_dir,
-            &session.user_hash,
-            draft_id,
-            storage.as_ref(),
-        )
-        .await?
+    // Reject an oversized attachment set from the stored sizes before any blob
+    // is read, then bound how many requests hold attachment data in RAM at once.
+    // The permit lives until the message has been sent and appended to Sent.
+    let stored_attachments = if let Some(ref draft_id) = req.draft_id {
+        draft_attachment_records(&config, &session.user_hash, draft_id)?
     } else {
-        vec![]
+        Vec::new()
     };
+    let loads_attachment_data = !stored_attachments.is_empty()
+        || (imap_source.is_some() && !imap_attachment_refs.is_empty());
+    let build_permit = if loads_attachment_data {
+        Some(build_limiter.acquire().await?)
+    } else {
+        None
+    };
+    let mut attachments = read_draft_attachments(storage.as_ref(), stored_attachments).await?;
     if let Some(source) = imap_source.as_ref() {
         let mut remote_attachments = crate::routes::drafts::load_imap_source_attachments(
             imap_client.as_ref(),
@@ -510,6 +530,18 @@ pub async fn send_message_handler(
         ));
     }
 
+    // Final check on what is really in memory (includes IMAP-sourced attachments,
+    // attached public keys and signature images) before the MIME builder copies it.
+    let attachment_bytes: u64 = attachments
+        .iter()
+        .map(|attachment| attachment.data.len() as u64)
+        .sum();
+    ensure_attachments_fit(
+        config.max_message_size_bytes(),
+        attachment_bytes,
+        attachments.len(),
+    )?;
+
     let message = SendableMessage {
         from: from_address,
         to: req.to,
@@ -532,8 +564,107 @@ pub async fn send_message_handler(
         max_message_size_bytes: config.max_message_size_bytes(),
     };
 
+    let imap_creds = ImapCredentials {
+        host: session.imap_host.clone(),
+        port: session.imap_port,
+        tls: session.imap_tls,
+        tls_verify: session.imap_tls_verify,
+        email: session.email.clone(),
+        password: session.password.clone(),
+    };
+
+    let undo_window = config.undo_send_window_secs;
+    if undo_window == 0 {
+        let message_id = dispatch_message(
+            &config,
+            smtp_client.as_ref(),
+            &smtp_creds,
+            &message,
+            imap_client.as_ref(),
+            &imap_creds,
+            &session.user_hash,
+            req.draft_id.as_deref(),
+            imap_source.as_ref(),
+            storage.as_ref(),
+        )
+        .await?;
+        return Ok(Json(SendResponse {
+            status: "sent".to_string(),
+            message_id,
+            pending_send_id: None,
+            undo_window_secs: None,
+        })
+        .into_response());
+    }
+
+    // Undo Send: stage the already-built message and let the client cancel
+    // it for `undo_window` seconds before anything is actually dispatched.
+    // The MessageBuildLimiter permit (if any) is moved into the delayed task
+    // below and held for the whole window, exactly as it is already held
+    // through an immediate send; this is what bounds how many undo-pending
+    // sends can hold attachment data in memory at once.
+    let pending_id = undo_registry.stage();
+    let draft_id = req.draft_id.clone();
+    let dispatch_config = config.clone();
+    let dispatch_smtp_client = smtp_client.clone();
+    let dispatch_imap_client = imap_client.clone();
+    let dispatch_storage = storage.clone();
+    let dispatch_registry = undo_registry.clone();
+    let dispatch_user_hash = session.user_hash.clone();
+    let dispatch_pending_id = pending_id.clone();
+    tokio::spawn(async move {
+        let _permit = build_permit;
+        tokio::time::sleep(Duration::from_secs(undo_window)).await;
+        if !dispatch_registry.begin_dispatch(&dispatch_pending_id) {
+            // Cancelled during the undo window: never contact SMTP.
+            return;
+        }
+        let result = dispatch_message(
+            &dispatch_config,
+            dispatch_smtp_client.as_ref(),
+            &smtp_creds,
+            &message,
+            dispatch_imap_client.as_ref(),
+            &imap_creds,
+            &dispatch_user_hash,
+            draft_id.as_deref(),
+            imap_source.as_ref(),
+            dispatch_storage.as_ref(),
+        )
+        .await;
+        match result {
+            Ok(message_id) => dispatch_registry.record_sent(&dispatch_pending_id, message_id),
+            Err(error) => dispatch_registry.record_failed(&dispatch_pending_id, error.to_string()),
+        }
+    });
+
+    Ok(Json(SendResponse {
+        status: "pending".to_string(),
+        message_id: String::new(),
+        pending_send_id: Some(pending_id),
+        undo_window_secs: Some(undo_window),
+    })
+    .into_response())
+}
+
+/// Sends the already-built `message` over SMTP, appends it to the Sent
+/// folder, and cleans up the source draft/IMAP snapshot it came from. Shared
+/// by an immediate send and the delayed dispatch after an Undo Send window.
+#[allow(clippy::too_many_arguments)]
+async fn dispatch_message(
+    config: &AppConfig,
+    smtp_client: &dyn SmtpClient,
+    smtp_creds: &SmtpCredentials,
+    message: &SendableMessage,
+    imap_client: &dyn ImapClient,
+    imap_creds: &ImapCredentials,
+    user_hash: &str,
+    draft_id: Option<&str>,
+    imap_source: Option<&ImapDraftSource>,
+    storage: &dyn BlobStorage,
+) -> Result<String, AppError> {
     let sent = smtp_client
-        .send_message(&smtp_creds, &message)
+        .send_message(smtp_creds, message)
         .await
         .map_err(|e| match e {
             crate::smtp::client::SmtpError::MessageTooLarge { actual, limit } => {
@@ -547,17 +678,8 @@ pub async fn send_message_handler(
         })?;
     let message_id = sent.message_id.clone();
 
-    let imap_creds = ImapCredentials {
-        host: session.imap_host.clone(),
-        port: session.imap_port,
-        tls: session.imap_tls,
-        tls_verify: session.imap_tls_verify,
-        email: session.email.clone(),
-        password: session.password.clone(),
-    };
-
     {
-        let database = db::pool::UserDb::new(&config.data_dir, &session.user_hash);
+        let database = db::pool::UserDb::new(&config.data_dir, user_hash);
         let sent_folder = database
             .run(|conn| {
                 Ok(db::special_folders::get_role(conn, "sent")?
@@ -568,7 +690,7 @@ pub async fn send_message_handler(
             .unwrap_or_else(|_| "Sent".to_string());
 
         match imap_client
-            .append_message(&imap_creds, &sent_folder, &sent.rfc822, &["\\Seen"])
+            .append_message(imap_creds, &sent_folder, &sent.rfc822, &["\\Seen"])
             .await
         {
             Ok(()) => {
@@ -587,62 +709,93 @@ pub async fn send_message_handler(
     }
 
     let mut source_removed_with_local_draft = false;
-    if let Some(ref draft_id) = req.draft_id {
-        if let Ok(conn) = db::pool::open_user_db(&config.data_dir, &session.user_hash)
+    if let Some(draft_id) = draft_id {
+        if let Ok(conn) = db::pool::open_user_db(&config.data_dir, user_hash)
             && let Ok(Some(draft)) = db::drafts::get_draft(&conn, draft_id)
         {
-            source_removed_with_local_draft = imap_source.as_ref().is_some_and(|source| {
+            source_removed_with_local_draft = imap_source.is_some_and(|source| {
                 draft.remote_folder.as_deref() == Some(source.folder.as_str())
                     && draft.remote_uid == Some(source.uid)
                     && draft.remote_uid_validity == Some(source.uid_validity)
             });
-            crate::routes::drafts::remove_remote_draft_snapshot(
-                imap_client.as_ref(),
-                &imap_creds,
-                &draft,
-            )
+            crate::routes::drafts::remove_remote_draft_snapshot(imap_client, imap_creds, &draft)
                 .await;
         }
-        cleanup_draft(
-            &config.data_dir,
-            &session.user_hash,
-            draft_id,
-            storage.as_ref(),
-        )
-        .await;
+        cleanup_draft(&config.data_dir, user_hash, draft_id, storage).await;
     }
-    if !source_removed_with_local_draft && let Some(source) = imap_source.as_ref() {
-        crate::routes::drafts::remove_imap_source_snapshot(
-            imap_client.as_ref(),
-            &imap_creds,
-            source,
-            "",
-            0,
-        )
+    if !source_removed_with_local_draft && let Some(source) = imap_source {
+        crate::routes::drafts::remove_imap_source_snapshot(imap_client, imap_creds, source, "", 0)
             .await;
     }
 
-    Ok(Json(SendResponse {
-        status: "sent".to_string(),
-        message_id,
-    })
-    .into_response())
+    Ok(message_id)
 }
 
-async fn load_draft_attachments(
-    data_dir: &str,
+/// `DELETE /messages/send/{pending_send_id}`: cancels a message still inside
+/// its Undo Send window. `404` if the id is unknown/expired, `409` if it
+/// already started dispatching (or finished) and is too late to cancel.
+pub async fn cancel_pending_send(
+    Extension(undo_registry): Extension<Arc<UndoSendRegistry>>,
+    Path(pending_id): Path<String>,
+) -> Result<Response, AppError> {
+    match undo_registry.status(&pending_id) {
+        None => Err(AppError::NotFound(
+            "No pending send with that id".to_string(),
+        )),
+        Some(PendingOutcome::Pending) => {
+            if undo_registry.cancel(&pending_id) {
+                Ok(Json(serde_json::json!({ "status": "cancelled" })).into_response())
+            } else {
+                Err(AppError::BadRequest(
+                    "Too late to cancel; the message is already being sent".to_string(),
+                ))
+            }
+        }
+        Some(_) => Err(AppError::BadRequest(
+            "Too late to cancel; the message is already being sent".to_string(),
+        )),
+    }
+}
+
+/// `GET /messages/send/{pending_send_id}`: the current state of a staged
+/// send, for the client to poll once its Undo Send countdown ends.
+pub async fn pending_send_status(
+    Extension(undo_registry): Extension<Arc<UndoSendRegistry>>,
+    Path(pending_id): Path<String>,
+) -> Result<Response, AppError> {
+    match undo_registry.status(&pending_id) {
+        Some(outcome) => Ok(Json(outcome).into_response()),
+        None => Err(AppError::NotFound(
+            "No pending send with that id".to_string(),
+        )),
+    }
+}
+
+/// Draft attachment metadata, rejected with 413 when the stored sizes alone
+/// already exceed the message size limit. No blob data is read here.
+fn draft_attachment_records(
+    config: &AppConfig,
     user_hash: &str,
     draft_id: &str,
-    storage: &dyn BlobStorage,
-) -> Result<Vec<AttachmentData>, AppError> {
-    let conn = db::pool::open_user_db(data_dir, user_hash)
+) -> Result<Vec<db::drafts::DraftAttachment>, AppError> {
+    let conn = db::pool::open_user_db(&config.data_dir, user_hash)
         .map_err(|e| AppError::InternalError(format!("Failed to open database: {e}")))?;
-
-    let db_attachments =
+    let records =
         db::drafts::get_draft_attachments(&conn, draft_id).map_err(AppError::InternalError)?;
+    ensure_attachments_fit(
+        config.max_message_size_bytes(),
+        draft_attachments_total(&records),
+        records.len(),
+    )?;
+    Ok(records)
+}
 
-    let mut attachments = Vec::with_capacity(db_attachments.len());
-    for att in db_attachments {
+async fn read_draft_attachments(
+    storage: &dyn BlobStorage,
+    records: Vec<db::drafts::DraftAttachment>,
+) -> Result<Vec<AttachmentData>, AppError> {
+    let mut attachments = Vec::with_capacity(records.len());
+    for att in records {
         let data = storage::read_all(storage, &att.storage_key)
             .await
             .map_err(|e| {

src/routes/system_diagnostics.rs

@@ -189,7 +189,11 @@ fn trusted_contains(trusted: &[TrustedProxy], ip: &IpAddr) -> bool {
     trusted.iter().any(|entry| entry.contains(ip))
 }
 
-fn effective_client_ip(config: &AppConfig, headers: &HeaderMap, peer_ip: IpAddr) -> IpAddr {
+pub(crate) fn effective_client_ip(
+    config: &AppConfig,
+    headers: &HeaderMap,
+    peer_ip: IpAddr,
+) -> IpAddr {
     let trusted = config.parsed_trusted_proxies();
     if !trusted_contains(&trusted, &peer_ip) {
         return peer_ip;

src/routes/tests.rs

@@ -86,6 +86,12 @@ fn test_config_with_smtp(_static_dir: &str, data_dir: &str) -> Arc<AppConfig> {
         sieve_timeout_secs: 10,
         trusted_proxies: None,
         outgoing_headers: Vec::new(),
+        // Existing send tests assert on the immediate, synchronous send
+        // outcome (status/body), not the "Undo Send" staged-dispatch flow;
+        // keep that behavior disabled here so they keep testing what they
+        // were written to test. undo_send.rs/routes/send.rs have their own
+        // dedicated tests for the staged-dispatch path.
+        undo_send_window_secs: 0,
         ..AppConfig::default()
     })
 }
@@ -2720,3 +2726,254 @@ async fn export_contact_strips_control_chars_from_filename() {
         assert!(!cd.contains('\n'));
     }
 }
+
+fn multipart_upload_request(
+    uri: &str,
+    filename: &str,
+    payload: &[u8],
+    auth: &[(&'static str, String)],
+) -> Request<Body> {
+    let boundary = "rustbox-test-boundary";
+    let mut body = Vec::new();
+    body.extend_from_slice(
+        format!(
+            "--{boundary}\r\nContent-Disposition: form-data; name=\"file\"; filename=\"{filename}\"\r\nContent-Type: application/octet-stream\r\n\r\n"
+        )
+        .as_bytes(),
+    );
+    body.extend_from_slice(payload);
+    body.extend_from_slice(format!("\r\n--{boundary}--\r\n").as_bytes());
+    let mut req = Request::builder()
+        .method("POST")
+        .uri(uri)
+        .header(
+            "content-type",
+            format!("multipart/form-data; boundary={boundary}"),
+        )
+        .header("x-requested-with", "XMLHttpRequest");
+    for (name, value) in auth {
+        req = req.header(*name, value.as_str());
+    }
+    req.body(Body::from(body)).unwrap()
+}
+
+async fn error_code_of(response: axum::response::Response) -> String {
+    let body = response.into_body().collect().await.unwrap().to_bytes();
+    let json: serde_json::Value = serde_json::from_slice(&body).unwrap();
+    json["error"]["code"]
+        .as_str()
+        .unwrap_or_default()
+        .to_string()
+}
+
+#[tokio::test]
+async fn upload_over_the_message_size_limit_is_rejected_while_streaming() {
+    let static_dir = setup_static_dir();
+    let data_dir = TempDir::new().unwrap();
+    let mut cfg = (*test_config_with_imap(
+        static_dir.path().to_str().unwrap(),
+        data_dir.path().to_str().unwrap(),
+    ))
+    .clone();
+    cfg.max_attachment_size_mb = 10;
+    cfg.max_message_size_mb = 1;
+    let store = test_store();
+    let (browser_id, account_id, token) = setup_test_account(&store, "alice@example.com");
+    let user_hash = crate::auth::user_data::hash_email("alice@example.com");
+    provision_user_db(data_dir.path().to_str().unwrap(), &user_hash);
+    let app = create_router(
+        Arc::new(cfg),
+        store,
+        Arc::new(MockImapClient::new()),
+        test_smtp_client(),
+        test_search_engine(data_dir.path().to_str().unwrap()),
+        test_event_bus(),
+        test_idle_manager(),
+    );
+    let auth = auth_headers(&browser_id, &account_id, &token);
+
+    // A single 2 MiB file cannot fit a 1 MiB message even though it is below
+    // the per-attachment limit.
+    let response = app
+        .clone()
+        .oneshot(multipart_upload_request(
+            "/api/drafts/limit-draft/attachments",
+            "big.bin",
+            &vec![7u8; 2 * 1024 * 1024],
+            &auth,
+        ))
+        .await
+        .unwrap();
+    assert_eq!(response.status(), StatusCode::PAYLOAD_TOO_LARGE);
+    assert_eq!(error_code_of(response).await, "PAYLOAD_TOO_LARGE");
+
+    // Two files that each fit but not together: the second one is refused.
+    for (index, expected) in [(1, StatusCode::OK), (2, StatusCode::PAYLOAD_TOO_LARGE)] {
+        let response = app
+            .clone()
+            .oneshot(multipart_upload_request(
+                "/api/drafts/limit-draft-2/attachments",
+                &format!("part-{index}.bin"),
+                &vec![1u8; 500_000],
+                &auth,
+            ))
+            .await
+            .unwrap();
+        assert_eq!(response.status(), expected, "upload #{index}");
+    }
+
+    let conn =
+        crate::db::pool::open_user_db(data_dir.path().to_str().unwrap(), &user_hash).unwrap();
+    let stored = crate::db::drafts::get_draft_attachments(&conn, "limit-draft-2").unwrap();
+    assert_eq!(stored.len(), 1);
+    assert!(
+        crate::db::drafts::get_draft_attachments(&conn, "limit-draft")
+            .unwrap()
+            .is_empty()
+    );
+}
+
+#[tokio::test]
+async fn send_rejects_oversized_draft_attachments_before_reading_any_blob() {
+    let static_dir = setup_static_dir();
+    let data_dir = TempDir::new().unwrap();
+    let config = test_config_with_smtp(
+        static_dir.path().to_str().unwrap(),
+        data_dir.path().to_str().unwrap(),
+    );
+    let store = test_store();
+    let (browser_id, account_id, token) = setup_test_account(&store, "alice@example.com");
+    let user_hash = crate::auth::user_data::hash_email("alice@example.com");
+    let conn =
+        crate::db::pool::open_user_db(data_dir.path().to_str().unwrap(), &user_hash).unwrap();
+    crate::db::drafts::upsert_draft(
+        &conn,
+        "huge-draft",
+        "",
+        "",
+        "",
+        "",
+        "",
+        None,
+        None,
+        None,
+        false,
+        "normal",
+        "html",
+        "none",
+        false,
+        false,
+        false,
+    )
+    .unwrap();
+    // The recorded size is far above max_message_size_mb and the blob does not
+    // exist: a 413 (not a 500 read error) proves nothing was loaded.
+    crate::db::drafts::add_draft_attachment(
+        &conn,
+        &crate::db::drafts::NewDraftAttachment {
+            id: "huge-att",
+            draft_id: "huge-draft",
+            filename: "huge.bin",
+            content_type: "application/octet-stream",
+            size: 200 * 1024 * 1024,
+            storage_key: "missing/blob",
+            checksum_sha256: None,
+        },
+    )
+    .unwrap();
+
+    let mock_smtp: Arc<dyn SmtpClient> = Arc::new(MockSmtpClient::new());
+    let app = create_router(
+        config,
+        store,
+        Arc::new(MockImapClient::new()),
+        mock_smtp,
+        test_search_engine(data_dir.path().to_str().unwrap()),
+        test_event_bus(),
+        test_idle_manager(),
+    );
+    let mut req = Request::builder()
+        .method("POST")
+        .uri("/api/messages/send")
+        .header("x-requested-with", "XMLHttpRequest")
+        .header("content-type", "application/json");
+    for (name, value) in auth_headers(&browser_id, &account_id, &token) {
+        req = req.header(name, value);
+    }
+    let response = app
+        .oneshot(
+            req.body(Body::from(
+                r#"{"to":["bob@example.com"],"subject":"Big","text_body":"x","draft_id":"huge-draft"}"#,
+            ))
+            .unwrap(),
+        )
+        .await
+        .unwrap();
+    assert_eq!(response.status(), StatusCode::PAYLOAD_TOO_LARGE);
+    assert_eq!(error_code_of(response).await, "PAYLOAD_TOO_LARGE");
+}
+
+#[tokio::test]
+async fn sends_with_attachments_release_their_build_slot() {
+    let static_dir = setup_static_dir();
+    let data_dir = TempDir::new().unwrap();
+    let mut cfg = (*test_config_with_smtp(
+        static_dir.path().to_str().unwrap(),
+        data_dir.path().to_str().unwrap(),
+    ))
+    .clone();
+    // A single slot and a short wait: the second send only succeeds when the
+    // first one gave its permit back.
+    cfg.max_concurrent_message_builds = 1;
+    cfg.message_build_wait_secs = 1;
+    let store = test_store();
+    let (browser_id, account_id, token) = setup_test_account(&store, "alice@example.com");
+    let user_hash = crate::auth::user_data::hash_email("alice@example.com");
+    provision_user_db(data_dir.path().to_str().unwrap(), &user_hash);
+    let mock_imap = Arc::new(MockImapClient::new());
+    let app = create_router(
+        Arc::new(cfg),
+        store,
+        mock_imap.clone(),
+        Arc::new(MockSmtpClient::new()),
+        test_search_engine(data_dir.path().to_str().unwrap()),
+        test_event_bus(),
+        test_idle_manager(),
+    );
+    let auth = auth_headers(&browser_id, &account_id, &token);
+
+    for draft_id in ["slot-draft-1", "slot-draft-2"] {
+        let upload = app
+            .clone()
+            .oneshot(multipart_upload_request(
+                &format!("/api/drafts/{draft_id}/attachments"),
+                "note.txt",
+                b"hello attachment",
+                &auth,
+            ))
+            .await
+            .unwrap();
+        assert_eq!(upload.status(), StatusCode::OK);
+
+        let mut req = Request::builder()
+            .method("POST")
+            .uri("/api/messages/send")
+            .header("x-requested-with", "XMLHttpRequest")
+            .header("content-type", "application/json");
+        for (name, value) in &auth {
+            req = req.header(*name, value.as_str());
+        }
+        let response = app
+            .clone()
+            .oneshot(
+                req.body(Body::from(format!(
+                    r#"{{"to":["bob@example.com"],"subject":"With file","text_body":"see attached","draft_id":"{draft_id}"}}"#
+                )))
+                .unwrap(),
+            )
+            .await
+            .unwrap();
+        assert_eq!(response.status(), StatusCode::OK, "send for {draft_id}");
+    }
+    assert_eq!(mock_imap.appended.lock().unwrap().len(), 2);
+}

src/undo_send.rs

@@ -0,0 +1,194 @@
+//! In-memory staging for "Undo Send".
+//!
+//! When `undo_send_window_secs > 0`, a fully built outgoing message is held
+//! in memory for that many seconds before it is actually dispatched to SMTP,
+//! so the sender can cancel it. Nothing here is persisted: a server restart
+//! during the window loses any message still staged, the same way a message
+//! already queued by any mail server can be lost if the process is killed
+//! mid-flight. The window is meant to be short (seconds, not minutes) for
+//! exactly this reason.
+//!
+//! State transitions are `Pending -> Cancelled` (a user clicks "Undo") or
+//! `Pending -> Dispatching -> Sent | Failed` (the window elapses). Both the
+//! cancel handler and the delayed dispatch task race to leave `Pending`, but
+//! only one of them can win because the transition happens under a single
+//! mutex: whichever reaches it first decides the outcome.
+
+use std::collections::HashMap;
+use std::sync::Mutex;
+use std::time::{SystemTime, UNIX_EPOCH};
+
+/// How long a finished (sent/cancelled/failed) entry is kept around so a late
+/// status poll from the client still finds it.
+const RESULT_RETENTION_SECS: u64 = 120;
+
+#[derive(Clone, Debug, PartialEq, Eq, serde::Serialize)]
+#[serde(tag = "status", rename_all = "snake_case")]
+pub enum PendingOutcome {
+    Pending,
+    Dispatching,
+    Sent { message_id: String },
+    Cancelled,
+    Failed { error: String },
+}
+
+struct PendingEntry {
+    outcome: PendingOutcome,
+    recorded_at: u64,
+}
+
+fn now_epoch() -> u64 {
+    SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .unwrap_or_default()
+        .as_secs()
+}
+
+#[derive(Default)]
+pub struct UndoSendRegistry {
+    entries: Mutex<HashMap<String, PendingEntry>>,
+}
+
+impl UndoSendRegistry {
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    fn sweep(entries: &mut HashMap<String, PendingEntry>) {
+        let now = now_epoch();
+        entries.retain(|_, entry| {
+            matches!(
+                entry.outcome,
+                PendingOutcome::Pending | PendingOutcome::Dispatching
+            ) || now.saturating_sub(entry.recorded_at) < RESULT_RETENTION_SECS
+        });
+    }
+
+    /// Registers a new pending send and returns its id.
+    pub fn stage(&self) -> String {
+        let id = uuid::Uuid::new_v4().to_string();
+        let mut entries = self.entries.lock().expect("undo-send registry lock");
+        Self::sweep(&mut entries);
+        entries.insert(
+            id.clone(),
+            PendingEntry {
+                outcome: PendingOutcome::Pending,
+                recorded_at: now_epoch(),
+            },
+        );
+        id
+    }
+
+    /// Cancels a still-pending send. Returns `true` if this call is the one
+    /// that cancelled it; `false` if it was already dispatching/finished or
+    /// the id is unknown/expired.
+    pub fn cancel(&self, id: &str) -> bool {
+        let mut entries = self.entries.lock().expect("undo-send registry lock");
+        match entries.get_mut(id) {
+            Some(entry) if entry.outcome == PendingOutcome::Pending => {
+                entry.outcome = PendingOutcome::Cancelled;
+                entry.recorded_at = now_epoch();
+                true
+            }
+            _ => false,
+        }
+    }
+
+    /// Called by the delayed dispatch task once its wait is over, right
+    /// before it would contact SMTP. Returns `true` if this call is the one
+    /// that claimed the send (i.e. it was not cancelled in the meantime);
+    /// the caller must then actually dispatch and record the result.
+    pub fn begin_dispatch(&self, id: &str) -> bool {
+        let mut entries = self.entries.lock().expect("undo-send registry lock");
+        match entries.get_mut(id) {
+            Some(entry) if entry.outcome == PendingOutcome::Pending => {
+                entry.outcome = PendingOutcome::Dispatching;
+                true
+            }
+            _ => false,
+        }
+    }
+
+    pub fn record_sent(&self, id: &str, message_id: String) {
+        let mut entries = self.entries.lock().expect("undo-send registry lock");
+        if let Some(entry) = entries.get_mut(id) {
+            entry.outcome = PendingOutcome::Sent { message_id };
+            entry.recorded_at = now_epoch();
+        }
+    }
+
+    pub fn record_failed(&self, id: &str, error: String) {
+        let mut entries = self.entries.lock().expect("undo-send registry lock");
+        if let Some(entry) = entries.get_mut(id) {
+            entry.outcome = PendingOutcome::Failed { error };
+            entry.recorded_at = now_epoch();
+        }
+    }
+
+    pub fn status(&self, id: &str) -> Option<PendingOutcome> {
+        let mut entries = self.entries.lock().expect("undo-send registry lock");
+        Self::sweep(&mut entries);
+        entries.get(id).map(|entry| entry.outcome.clone())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn a_pending_send_can_be_cancelled_exactly_once() {
+        let registry = UndoSendRegistry::new();
+        let id = registry.stage();
+        assert_eq!(registry.status(&id), Some(PendingOutcome::Pending));
+        assert!(registry.cancel(&id));
+        assert_eq!(registry.status(&id), Some(PendingOutcome::Cancelled));
+        // A second cancel is a no-op: the first one already won the race.
+        assert!(!registry.cancel(&id));
+    }
+
+    #[test]
+    fn dispatch_cannot_start_once_cancelled() {
+        let registry = UndoSendRegistry::new();
+        let id = registry.stage();
+        assert!(registry.cancel(&id));
+        assert!(!registry.begin_dispatch(&id));
+    }
+
+    #[test]
+    fn cancel_cannot_win_once_dispatch_has_begun() {
+        let registry = UndoSendRegistry::new();
+        let id = registry.stage();
+        assert!(registry.begin_dispatch(&id));
+        assert!(!registry.cancel(&id));
+        registry.record_sent(&id, "msg-1".to_string());
+        assert_eq!(
+            registry.status(&id),
+            Some(PendingOutcome::Sent {
+                message_id: "msg-1".to_string()
+            })
+        );
+    }
+
+    #[test]
+    fn a_dispatch_that_fails_is_recorded_as_failed() {
+        let registry = UndoSendRegistry::new();
+        let id = registry.stage();
+        assert!(registry.begin_dispatch(&id));
+        registry.record_failed(&id, "SMTP timed out".to_string());
+        assert_eq!(
+            registry.status(&id),
+            Some(PendingOutcome::Failed {
+                error: "SMTP timed out".to_string()
+            })
+        );
+    }
+
+    #[test]
+    fn an_unknown_id_has_no_status() {
+        let registry = UndoSendRegistry::new();
+        assert_eq!(registry.status("does-not-exist"), None);
+        assert!(!registry.cancel("does-not-exist"));
+        assert!(!registry.begin_dispatch("does-not-exist"));
+    }
+}

src/web/css/50-settings.css

@@ -364,6 +364,44 @@
   width: 100%;
 }
 
+.snoozed-message-list {
+  display: grid;
+  gap: 8px;
+}
+
+.snoozed-message-row {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 12px;
+  padding: 8px 10px;
+  border: 1px solid var(--border, #e2e2e2);
+  border-radius: 8px;
+}
+
+.snoozed-message-info {
+  display: grid;
+  gap: 2px;
+  min-width: 0;
+}
+
+.snoozed-message-info strong {
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+.snoozed-message-info span {
+  color: var(--muted);
+  font-size: 0.85em;
+}
+
+.snoozed-message-actions {
+  display: flex;
+  gap: 6px;
+  flex-shrink: 0;
+}
+
 .app-prompt-actions> :first-child {
   margin-right: auto;
 }

src/web/js/40-messages-reader.js

@@ -98,6 +98,7 @@ async function loadMessages(reset = false, options = {}) {
     }
     $("#connection-label").textContent = "Connected";
     renderMessages();
+    void applySnoozeHiding();
     const desiredScroll = savedState?.scrollTop ?? previousScrollTop;
     if (mode === "pagination") {
       requestAnimationFrame(() => { list.scrollTop = 0; });
@@ -302,6 +303,24 @@ async function quickUpdateMessageFlag(message, flag, add, successMessage) {
   }
 }
 
+// Hides rows for messages that are currently snoozed in this folder. This is
+// a purely visual, best-effort filter on top of the already-rendered list:
+// it never changes state.messages/state.total, so pagination/counts/caching
+// above are completely unaffected. A message simply stops being hidden once
+// its wake time passes and the folder is reloaded or reopened.
+async function applySnoozeHiding() {
+  if (state.searchContext) return;
+  const folder = state.folder;
+  try {
+    const data = await request(`/folders/${encodeURIComponent(folder)}/snoozed-uids`, { method: "GET" });
+    const sleeping = new Set((data.uids || []).map(String));
+    if (!sleeping.size || folder !== state.folder) return;
+    for (const row of $$(".message-row", $("#message-list"))) {
+      if (sleeping.has(row.dataset.uid)) row.style.display = "none";
+    }
+  } catch (_) { /* best-effort visual filter only; never blocks the folder view */ }
+}
+
 function renderMessages() {
   $("#folder-title").textContent = state.folder;
   const folderTotal = Number(state.folders.find((folder) => folder.name === state.folder)?.total_count);
@@ -401,12 +420,24 @@ function renderMessages() {
     });
     row.addEventListener("dragend", () => row.classList.remove("dragging"));
     row.addEventListener("click", (event) => {
+      if (state.selectionMode) {
         if (event.shiftKey) {
           event.preventDefault();
           selectMessageRange(message);
           return;
         }
-      if (state.selectionMode || event.ctrlKey || event.metaKey) return setMessageSelected(message, !state.selectedMessages.has(messageKey(message)));
+        return setMessageSelected(message, !state.selectedMessages.has(messageKey(message)));
+      }
+      if (event.ctrlKey || event.metaKey) {
+        event.preventDefault();
+        openMessageInNewTab(folder, message.uid);
+        return;
+      }
+      if (event.shiftKey) {
+        event.preventDefault();
+        openMessageInPopup(folder, message.uid);
+        return;
+      }
       setMessageSelectionAnchor(message);
       openMessage(folder, message.uid);
     });
@@ -455,16 +486,37 @@ async function senderIsSavedContact(email) {
 }
 
 
-function readerFullscreenUrl(detail = state.currentDetail) {
+function messageDeepLinkUrl(folder, uid) {
   const url = new URL(location.href);
-  if (detail?.folder && Number.isFinite(Number(detail.uid))) {
-    url.searchParams.set("mail_folder", detail.folder);
-    url.searchParams.set("mail_uid", String(detail.uid));
+  url.searchParams.set("mail_folder", folder);
+  url.searchParams.set("mail_uid", String(uid));
   url.searchParams.set("mail_fullscreen", "1");
-  }
   return url;
 }
 
+function readerFullscreenUrl(detail = state.currentDetail) {
+  if (detail?.folder && Number.isFinite(Number(detail.uid))) return messageDeepLinkUrl(detail.folder, detail.uid);
+  return new URL(location.href);
+}
+
+// Gmail-style modifier clicks on a message row, active only outside selection
+// mode (inside selection mode the same modifiers keep doing range/toggle
+// selection, see the row click handler below).
+function openMessageInNewTab(folder, uid) {
+  window.open(messageDeepLinkUrl(folder, uid), "_blank", "noopener");
+}
+
+function openMessageInPopup(folder, uid) {
+  const width = Math.max(420, Math.min(900, Math.round(innerWidth * 0.8)));
+  const height = Math.max(360, Math.min(760, Math.round(innerHeight * 0.85)));
+  const left = Math.max(0, Math.round((innerWidth - width) / 2) + (window.screenX || 0));
+  const top = Math.max(0, Math.round((innerHeight - height) / 2) + (window.screenY || 0));
+  const features = `popup=1,noopener,width=${width},height=${height},left=${left},top=${top}`;
+  // A stable window name per message re-focuses the same popup on a second
+  // shift-click instead of spawning duplicates, matching normal browser behavior.
+  window.open(messageDeepLinkUrl(folder, uid), `rustbox-message-${folder}-${uid}`, features);
+}
+
 function restoreReaderScroll() {
   const reader = $("#reader-content");
   if (!reader) return;

src/web/js/50-compose.js

@@ -1788,6 +1788,32 @@ function buildReferences(detail) {
   return values.length ? values.join(" ") : null;
 }
 
+// "Undo Send": the server held the just-sent message back for a few seconds
+// instead of dispatching it immediately. Show a toast with an Undo action
+// for the whole window, then poll once for the final result so a send that
+// actually failed in the background is still reported.
+function notifyUndoSendStaged(pendingId, windowSecs) {
+  const seconds = Math.max(0, windowSecs);
+  toast("Sending\u2026", "info", seconds * 1000 || 4000, {
+    label: "Undo",
+    onClick: async () => {
+      try {
+        await request(`/messages/send/${encodeURIComponent(pendingId)}`, { method: "DELETE" });
+        toast("Send cancelled", "success");
+      } catch (error) {
+        toast(error?.message || "Too late to cancel", "warning");
+      }
+    },
+  });
+  setTimeout(async () => {
+    try {
+      const final = await request(`/messages/send/${encodeURIComponent(pendingId)}`);
+      if (final?.status === "sent") toast("Message sent", "success");
+      else if (final?.status === "failed") toast(`Could not send: ${final.error || "unknown error"}`, "error");
+    } catch (_) { /* already swept or still dispatching; nothing useful to report */ }
+  }, seconds * 1000 + 1500);
+}
+
 async function sendMessage(event) {
   event.preventDefault();
   if (state.composeUploading) return toast("Wait for the attachment upload to finish", "warning");
@@ -1821,7 +1847,7 @@ async function sendMessage(event) {
   setBusy(send, true);
   const editor = $("#compose-editor");
   try {
-    await request("/messages/send", {
+    const sendResult = await request("/messages/send", {
       method: "POST",
       body: JSON.stringify({
         to: parseRecipients($("#compose-to").value),
@@ -1865,7 +1891,11 @@ async function sendMessage(event) {
     state.pgpRecipientStatus = [];
     $("#compose-pgp-passphrase").value = "";
     updateComposeMessageSize();
+    if (sendResult?.status === "pending" && sendResult.pending_send_id) {
+      notifyUndoSendStaged(sendResult.pending_send_id, Number(sendResult.undo_window_secs) || 0);
+    } else {
       toast("Message sent", "success");
+    }
     await loadFolders();
   } catch (error) {
     state.composeDirty = true;

src/web/js/60-mail-actions-search.js

@@ -181,6 +181,131 @@ async function copyCurrentTo(targetFolder) {
   } catch (error) { toast(error.message, "error"); }
 }
 
+// Snoozing hides a message from its folder listing until a chosen wake time.
+// It is purely local client/server cache state: nothing moves on the real
+// IMAP server, so a snooze never risks the actual mailbox.
+function snoozePresetOptions() {
+  const now = new Date();
+  const laterToday = new Date(now.getTime() + 3 * 60 * 60 * 1000);
+  const tomorrow = new Date(now);
+  tomorrow.setDate(tomorrow.getDate() + 1);
+  tomorrow.setHours(9, 0, 0, 0);
+  const nextWeek = new Date(now);
+  nextWeek.setDate(nextWeek.getDate() + (8 - nextWeek.getDay()) % 7 || 7);
+  nextWeek.setHours(9, 0, 0, 0);
+  const weekend = new Date(now);
+  const daysToSaturday = (6 - weekend.getDay() + 7) % 7 || 7;
+  weekend.setDate(weekend.getDate() + daysToSaturday);
+  weekend.setHours(9, 0, 0, 0);
+  return [
+    { label: `Later today (${formatDate(laterToday.toISOString(), true)})`, value: String(Math.floor(laterToday.getTime() / 1000)) },
+    { label: `Tomorrow (${formatDate(tomorrow.toISOString(), true)})`, value: String(Math.floor(tomorrow.getTime() / 1000)) },
+    { label: `This weekend (${formatDate(weekend.toISOString(), true)})`, value: String(Math.floor(weekend.getTime() / 1000)) },
+    { label: `Next week (${formatDate(nextWeek.toISOString(), true)})`, value: String(Math.floor(nextWeek.getTime() / 1000)) },
+  ];
+}
+
+async function promptSnoozeCurrent() {
+  if (!state.currentDetail) return;
+  const wakeAt = await appDialog({
+    title: "Snooze until\u2026",
+    selectOptions: snoozePresetOptions(),
+    confirmLabel: "Snooze",
+  });
+  if (!wakeAt) return;
+  await snoozeCurrent(Number(wakeAt));
+}
+
+async function snoozeCurrent(wakeAtEpochSeconds) {
+  if (!state.currentDetail || !Number.isFinite(wakeAtEpochSeconds)) return;
+  const detail = state.currentDetail;
+  const nextTarget = nextMessageTargetAfterRemoval(detail.folder, detail.uid);
+  try {
+    await request(`/messages/${encodeURIComponent(detail.folder)}/${detail.uid}/snooze`, {
+      method: "POST",
+      body: JSON.stringify({ wake_at: wakeAtEpochSeconds }),
+    });
+    await removeCurrentMessageFromView(detail.folder, detail.uid, nextTarget);
+    await refreshFolderListOnly();
+    toast(`Snoozed until ${formatDate(new Date(wakeAtEpochSeconds * 1000).toISOString(), true)}`, "success");
+  } catch (error) {
+    toast(error.message, "error");
+  }
+}
+
+async function showSnoozedMessages() {
+  let data;
+  try {
+    data = await request("/messages/snoozed", { method: "GET" });
+  } catch (error) {
+    toast(error.message, "error");
+    return;
+  }
+  const items = data.messages || [];
+  const dialog = el("dialog", "dialog app-prompt-dialog");
+  const form = el("div", "dialog-card app-prompt-card");
+  const header = el("header", "dialog-header");
+  header.append(el("strong", "", "Snoozed messages"));
+  const close = el("button", "icon-button");
+  close.type = "button";
+  close.setAttribute("aria-label", "Close");
+  close.innerHTML = svgIcon("x");
+  close.addEventListener("click", () => dialog.close());
+  header.append(close);
+  const body = el("div", "app-prompt-body");
+  if (!items.length) {
+    body.append(el("p", "app-prompt-message", "No snoozed messages."));
+  } else {
+    const list = el("div", "snoozed-message-list");
+    for (const item of items) {
+      const row = el("div", "snoozed-message-row");
+      const info = el("div", "snoozed-message-info");
+      info.append(
+        el("strong", "", item.subject || "(no subject)"),
+        el("span", "", item.from_name || item.from_address || ""),
+        el("span", "", `Wakes ${formatDate(new Date(item.wake_at * 1000).toISOString(), true)}`),
+      );
+      const actions = el("div", "snoozed-message-actions");
+      const openBtn = el("button", "button quiet", "Open");
+      openBtn.type = "button";
+      openBtn.addEventListener("click", async () => { dialog.close(); await openMessage(item.message_folder, item.message_uid); });
+      const wakeBtn = el("button", "button quiet", "Unsnooze now");
+      wakeBtn.type = "button";
+      wakeBtn.addEventListener("click", async () => {
+        if (await unsnoozeMessage(item.message_folder, item.message_uid)) {
+          row.remove();
+          if (state.folder === item.message_folder) await refreshFolderListOnly();
+        }
+      });
+      actions.append(openBtn, wakeBtn);
+      row.append(info, actions);
+      list.append(row);
+    }
+    body.append(list);
+  }
+  const actions = el("footer", "dialog-actions app-prompt-actions");
+  const okBtn = el("button", "button primary", "Close");
+  okBtn.type = "button";
+  okBtn.addEventListener("click", () => dialog.close());
+  actions.append(okBtn);
+  form.append(header, body, actions);
+  dialog.append(form);
+  dialog.addEventListener("close", () => dialog.remove());
+  document.body.append(dialog);
+  dialog.showModal();
+}
+
+async function unsnoozeMessage(folder, uid) {
+  try {
+    await request(`/messages/${encodeURIComponent(folder)}/${uid}/snooze`, { method: "DELETE" });
+    toast("Message unsnoozed", "success");
+    return true;
+  } catch (error) {
+    toast(error.message, "error");
+    return false;
+  }
+}
+
 const SPAM_DEFAULT_FOLDER_KEY = "rustbox.defaultSpamFolder";
 
 function configuredBrowserSpamFolder() {
@@ -602,6 +727,8 @@ function openMessageContextMenu(x, y, message) {
     { label: flagged ? "Unflag" : "Flag", action: async () => { await ensureMessageOpen(message); await updateFlag("\\Flagged", !flagged); } },
     "separator",
     { label: "Archive", action: async () => { await ensureMessageOpen(message); await archiveCurrent(); } },
+    { label: "Snooze\u2026", action: async () => { await ensureMessageOpen(message); await promptSnoozeCurrent(); } },
+    { label: "View snoozed messages\u2026", action: async () => { await showSnoozedMessages(); } },
     { label: "Move to…", action: async () => { await ensureMessageOpen(message); const target = await promptFolder("Move to folder", message.folder || state.folder); if (target) await moveCurrentTo(target); } },
     { label: "Copy to…", action: async () => { await ensureMessageOpen(message); const target = await promptFolder("Copy to folder", message.folder || state.folder); if (target) await copyCurrentTo(target); } },
     { label: "Add label…", action: async () => { const tag = await promptTag("Add label"); if (tag) await addTagToMessage(message, tag); } },

src/web/js/95-bindings-boot.js

@@ -678,6 +678,7 @@ function bindEvents() {
       const globalKey = event.key.toLowerCase();
       if (globalKey === "c") { event.preventDefault(); openCompose("new"); return; }
       if (globalKey === "v") { event.preventDefault(); setSelectionMode(!state.selectionMode); return; }
+      if (globalKey === "b" && event.shiftKey) { event.preventDefault(); showSnoozedMessages(); return; }
     }
     if (appShortcut && state.currentDetail) {
       const key = event.key.toLowerCase();
@@ -691,6 +692,7 @@ function bindEvents() {
       else if (key === "a") { event.preventDefault(); openCompose("reply-all"); }
       else if (key === "f") { event.preventDefault(); openCompose("forward"); }
       else if (key === "e") { event.preventDefault(); archiveCurrent(); }
+      else if (key === "b") { event.preventDefault(); promptSnoozeCurrent(); }
       else if (key === "m") { event.preventDefault(); toggleUnread(); }
       else if (key === "s") { event.preventDefault(); toggleFlagged(); }
       else if (event.key === "!") { event.preventDefault(); junkCurrent(); }