Email

Sending emails requires additional setup and won’t work out of the box. You’ll need to configure your SMTP, provide host, username and password. You can set these up directly in the code or via environment variables. Refer to the corresponding section for more details.

Local development and testing

In development and integration tests, emails are caught by Mailpit  — a lightweight local SMTP server. No real emails are sent.

Development: Mailpit runs as a Docker container (defined in docker-compose-infra.dev.yml). Start it along with the other dev services:

docker-compose -f docker-compose-infra.dev.yml up -d

Once running, you can view all captured emails in the Mailpit web UI at http://localhost:8025 .

The backend dev config (application-dev.yml) points SMTP to Mailpit by default (localhost:1025), so no extra configuration is needed locally.

Integration tests: Mailpit is started automatically via Testcontainers (managed by TestcontainersConfig). Tests that send emails use mailpit() to assert emails were received.

Production

In production, Resend  is used as the SMTP provider (smtp.resend.com). Configure it via environment variables:

SMTP_HOST=smtp.resend.com
SMTP_PORT=2587
SMTP_USER=resend
SMTP_PASSWORD=your_resend_api_key
SMTP_SENDER=noreply@yourdomain.com

Adding your HTML templates

Emails are send via SpringBoot, you can create HTML email template in the resources/templates/email directory and send them using the sendHtmlEmail() method from the EmailService. However, creating responsive emails can be challenging.

To simplify this, I’ve integrated MJML . To use it, create a .mjml file in the resources/templates/email directory. During the Maven build, the mjml CLI will automatically generate the corresponding HTML email for you.