diff --git a/.env.example b/.env.example
index 3f004c9..8add7f7 100644
--- a/.env.example
+++ b/.env.example
@@ -37,13 +37,26 @@ EXPOSE_PORT=8785
 # Baza danych
 # ================================
 
-# Adres SQLAlchemy
-#
+# Wybór silnika bazy
+# Dozwolone:
+# - sqlite
+# - pgsql
+# - mysql
+DB_ENGINE=sqlite
+
+# Baza danych - dane
+DB_HOST=postgres
+DB_PORT=5432
+DB_NAME=ksef
+DB_USER=ksef
+DB_PASSWORD=ksef
+
+# Jeśli ustawisz DATABASE_URL ręcznie, ma priorytet nad DB_ENGINE/DB_*
 # Przykłady:
 # sqlite:///instance/app.db
-# postgresql://user:pass@localhost/dbname
-DATABASE_URL=sqlite:///instance/app.db
-
+# postgresql+psycopg://ksef:ksef@postgres:5432/ksef
+# mysql+pymysql://ksef:ksef@mysql:3306/ksef
+DATABASE_URL=sqlite:///db/sqlite/app.db
 
 # ================================
 # Redis / Cache / Rate limit
diff --git a/.gitignore b/.gitignore
index 31d1df0..a7fdf92 100644
--- a/.gitignore
+++ b/.gitignore
@@ -26,3 +26,4 @@ storage/*
 backups/*
 certs/*
 pdf/*
+db/*
\ No newline at end of file
diff --git a/Dockerfile b/Dockerfile
index 2068d49..e316ee9 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -25,6 +25,6 @@ COPY requirements.txt .
 RUN pip install --no-cache-dir -r requirements.txt
 
 COPY . .
-RUN mkdir -p instance storage/archive storage/pdf storage/backups
+RUN mkdir -p db storage/archive storage/pdf storage/backups
 
 CMD ["gunicorn", "-w", "1", "-k", "gthread", "--threads", "8", "-b", "0.0.0.0:5000", "run:app"]
diff --git a/config.py b/config.py
index 2cdc23e..ad2a9b1 100644
--- a/config.py
+++ b/config.py
@@ -7,12 +7,34 @@ load_dotenv(BASE_DIR / '.env')
 
 
 def _normalize_sqlalchemy_db_url(raw: str | None) -> str:
-    if not raw:
-        return f"sqlite:///{(BASE_DIR / 'instance' / 'app.db').resolve()}"
-    if raw.startswith('sqlite:///') and not raw.startswith('sqlite:////'):
-        rel = raw.replace('sqlite:///', '', 1)
-        return f"sqlite:///{(BASE_DIR / rel).resolve()}"
-    return raw
+    if raw:
+        raw = raw.strip()
+        if raw.startswith('postgres://'):
+            return raw.replace('postgres://', 'postgresql+psycopg://', 1)
+        if raw.startswith('sqlite:///') and not raw.startswith('sqlite:////'):
+            rel = raw.replace('sqlite:///', '', 1)
+            return f"sqlite:///{(BASE_DIR / rel).resolve()}"
+        return raw
+
+    db_engine = os.getenv('DB_ENGINE', 'sqlite').strip().lower()
+    db_host = os.getenv('DB_HOST', 'localhost').strip()
+    db_port = os.getenv('DB_PORT', '').strip()
+    db_name = os.getenv('DB_NAME', 'ksef').strip()
+    db_user = os.getenv('DB_USER', '').strip()
+    db_password = os.getenv('DB_PASSWORD', '').strip()
+
+    if db_engine == 'sqlite':
+        return f"sqlite:///{(BASE_DIR / 'db' / 'sqlite' / 'app.db').resolve()}"
+
+    if db_engine in ('pgsql', 'postgres', 'postgresql'):
+        port = db_port or '5432'
+        return f"postgresql+psycopg://{db_user}:{db_password}@{db_host}:{port}/{db_name}"
+
+    if db_engine == 'mysql':
+        port = db_port or '3306'
+        return f"mysql+pymysql://{db_user}:{db_password}@{db_host}:{port}/{db_name}"
+
+    raise ValueError(f"Nieobsługiwany DB_ENGINE: {db_engine}")
 
 
 def _path_from_env(name: str, default: Path) -> Path:
diff --git a/deploy_docker.sh b/deploy_docker.sh
index f1e6534..079d0c4 100755
--- a/deploy_docker.sh
+++ b/deploy_docker.sh
@@ -1,9 +1,18 @@
 #!/usr/bin/env sh
 set -eu
 
+DB_TARGET="${1:-sqlite}"
+
 STACK_NAME="${STACK_NAME:-ksef_app}"
 COMPOSE_FILE="${COMPOSE_FILE:-docker-compose.yml}"
 SSL_DIR="${SSL_DIR:-./deploy/caddy/ssl}"
+
+if [ -f .env ]; then
+  set -a
+  . ./.env
+  set +a
+fi
+
 APP_DOMAIN="${APP_DOMAIN:-localhost}"
 CERT_FILE="${CERT_FILE:-${SSL_DIR}/server.crt}"
 KEY_FILE="${KEY_FILE:-${SSL_DIR}/server.key}"
@@ -24,6 +33,38 @@ need_cmd openssl
 
 mkdir -p "$SSL_DIR"
 
+case "$DB_TARGET" in
+  sqlite)
+    export DB_ENGINE=sqlite
+    export DB_HOST=""
+    export DB_PORT=""
+    COMPOSE_PROFILES=""
+    mkdir -p ./db/sqlite
+    DB_PATH_INFO="./db/sqlite/app.db"
+    ;;
+  pgsql|postgres|postgresql)
+    export DB_ENGINE=pgsql
+    export DB_HOST="${DB_HOST:-postgres}"
+    export DB_PORT="${DB_PORT:-5432}"
+    COMPOSE_PROFILES="pgsql"
+    mkdir -p ./db/pgsql
+    DB_PATH_INFO="./db/pgsql"
+    ;;
+  mysql)
+    export DB_ENGINE=mysql
+    export DB_HOST="${DB_HOST:-mysql}"
+    export DB_PORT="${DB_PORT:-3306}"
+    COMPOSE_PROFILES="mysql"
+    mkdir -p ./db/mysql
+    DB_PATH_INFO="./db/mysql"
+    ;;
+  *)
+    printf 'Nieznany typ bazy: %s\n' "$DB_TARGET" >&2
+    printf 'Użycie: ./deploy_docker.sh [sqlite|pgsql|mysql]\n' >&2
+    exit 1
+    ;;
+esac
+
 if [ ! -f "$CERT_FILE" ] || [ ! -f "$KEY_FILE" ]; then
   log "Nie znaleziono certyfikatu SSL w katalogu ${SSL_DIR}, tworzę self-signed cert..."
   rm -f "$CERT_FILE" "$KEY_FILE"
@@ -38,22 +79,31 @@ else
   log "Znaleziono istniejący certyfikat SSL w katalogu ${SSL_DIR}."
 fi
 
-log "Pobieram najnowsze obrazy bazowe..."
-docker compose -f "$COMPOSE_FILE" pull
+log "Wybrany silnik bazy: ${DB_ENGINE}"
 
-log "Buduję obraz bez cache..."
-docker compose -f "$COMPOSE_FILE" build --no-cache
+if [ -n "$COMPOSE_PROFILES" ]; then
+  export COMPOSE_PROFILES
+  log "Aktywne profile Compose: ${COMPOSE_PROFILES}"
+else
+  unset COMPOSE_PROFILES || true
+  log "Brak aktywnych profili Compose"
+fi
 
-log "Zatrzymuję aktualny stack..."
+log "Pobieram najnowsze obrazy dla bieżącego stacka..."
+docker compose -p "$STACK_NAME" -f "$COMPOSE_FILE" pull
+
+log "Zatrzymuję aktualny stack projektu ${STACK_NAME}..."
 docker compose -p "$STACK_NAME" -f "$COMPOSE_FILE" stop || true
 
-log "Usuwam osierocone kontenery i stare nieużywane obrazy..."
+log "Usuwam kontenery i osierocone zasoby tylko dla projektu ${STACK_NAME}..."
 docker compose -p "$STACK_NAME" -f "$COMPOSE_FILE" down --remove-orphans || true
-docker image prune -af || true
-docker builder prune -af || true
 
-authoritative_stack="${STACK_NAME}"
-log "Uruchamiam stack ${authoritative_stack}..."
+log "Buduję obrazy projektu ${STACK_NAME} bez cache..."
+docker compose -p "$STACK_NAME" -f "$COMPOSE_FILE" build --no-cache
+
+log "Uruchamiam stack ${STACK_NAME}..."
 docker compose -p "$STACK_NAME" -f "$COMPOSE_FILE" up -d
 
 log "Deployment zakończony. Aplikacja powinna być dostępna pod https://${APP_DOMAIN}"
+log "Silnik bazy: ${DB_ENGINE}"
+log "Ścieżka danych bazy: ${DB_PATH_INFO}"
\ No newline at end of file
diff --git a/docker-compose.yml b/docker-compose.yml
index 6554a79..de7202d 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -3,14 +3,16 @@ services:
     build: .
     env_file: [.env]
     environment:
-      APP_PORT: 5000
-      APP_EXTERNAL_SCHEME: https
+      APP_PORT: ${APP_PORT:-5000}
+      APP_EXTERNAL_SCHEME: ${APP_EXTERNAL_SCHEME:-https}
       APP_EXTERNAL_HOST: ${APP_DOMAIN:-localhost}
       APP_EXTERNAL_PORT: ${EXPOSE_PORT:-8785}
       TZ: ${APP_TIMEZONE:-Europe/Warsaw}
     volumes:
       - ./:/app
-    depends_on: [redis]
+      - ./db/sqlite:/app/db/sqlite
+    depends_on:
+      - redis
     restart: unless-stopped
 
   redis:
@@ -19,6 +21,36 @@ services:
       - "6379:6379"
     restart: unless-stopped
 
+  postgres:
+    image: postgres:16-alpine
+    profiles: ["pgsql"]
+    environment:
+      POSTGRES_DB: ${DB_NAME:-ksef}
+      POSTGRES_USER: ${DB_USER:-ksef}
+      POSTGRES_PASSWORD: ${DB_PASSWORD:-ksef}
+      TZ: ${APP_TIMEZONE:-Europe/Warsaw}
+    volumes:
+      - ./db/pgsql:/var/lib/postgresql/data
+    ports:
+      - "${DB_PORT:-5432}:5432"
+    restart: unless-stopped
+
+  mysql:
+    image: mysql:8.4
+    profiles: ["mysql"]
+    command: --default-authentication-plugin=mysql_native_password
+    environment:
+      MYSQL_DATABASE: ${DB_NAME:-ksef}
+      MYSQL_USER: ${DB_USER:-ksef}
+      MYSQL_PASSWORD: ${DB_PASSWORD:-ksef}
+      MYSQL_ROOT_PASSWORD: ${MYSQL_ROOT_PASSWORD:-root}
+      TZ: ${APP_TIMEZONE:-Europe/Warsaw}
+    volumes:
+      - ./db/mysql:/var/lib/mysql
+    ports:
+      - "${DB_PORT:-3306}:3306"
+    restart: unless-stopped
+
   caddy:
     image: caddy:2-alpine
     env_file: [.env]
@@ -33,9 +65,10 @@ services:
       - ./deploy/caddy/ssl:/certs:ro
       - caddy_data:/data
       - caddy_config:/config
-    depends_on: [web]
+    depends_on:
+      - web
     restart: unless-stopped
 
 volumes:
   caddy_data:
-  caddy_config:
+  caddy_config:
\ No newline at end of file
diff --git a/requirements.txt b/requirements.txt
index 6b06c51..c8a6c95 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -22,3 +22,5 @@ cryptography==45.0.0
 xhtml2pdf==0.2.17
 psutil
 gunicorn==23.0.0
+PyMySQL==1.1.1
+psycopg==3.2.6