Email Delivery: Dev Mailcatcher & Production Mailgun

This application uses Symfony Mailer. We separate development and production delivery:

Development (Mailpit)

MAILER_DSN=smtp://mailer:1025

Usage:
1. Start stack: docker-compose up -d
2. Send an email from the app.
3. Open http://localhost:8025 to view captured emails.

Use the Mailgun API transport (symfony/mailgun-mailer bridge). Do not commit secrets.

MAILER_DSN=mailgun+api://${MAILGUN_API_KEY}:${MAILGUN_DOMAIN}@default?region=eu

region=eu is only needed if the Mailgun account/domain was created in Mailgun's EU region (common for .nl/EU-based senders). Drop it (or use region=us) if the domain lives in the US region.
Provide MAILGUN_API_KEY and MAILGUN_DOMAIN via:
- Real environment variables on the server/container, or
- Symfony secrets: php bin/console secrets:set MAILGUN_API_KEY (and dump for prod), or
- Orchestration secret stores (e.g., Docker/K8s).
The sending domain must be added and DNS-verified (SPF/DKIM/tracking CNAME) in the Mailgun dashboard before production sending will work reliably; unverified domains are rate-limited/sandboxed.

No Mailpit container is defined in the base compose.yaml, only in compose.override.yaml. This ensures it is used in development only.
To test email locally without Docker, you can:
- Run Mailpit on your host (ports 1025/8025) and set MAILER_DSN=smtp://127.0.0.1:1025 in .env.local.
If you need to use Mailgun SMTP instead of API, a DSN example: mailgun+smtp://USERNAME:PASSWORD@default?region=eu (username/password come from the Mailgun domain's SMTP credentials).
Use php bin/console app:mail:test you@example.com to send a quick test email against whatever MAILER_DSN is currently configured.