Run as a fully hardened production email server.
MailCue is an all-in-one email testing server packaged in a single Docker container. Unlike simple catch-all SMTPs, it provides a fully-featured mail stack with Postfix, Dovecot, SpamAssassin, DKIM/DMARC verification, and a modern React UI. Test your email workflows exactly as they behave in production with IMAP/POP3 access, API injection, real-time events, and GPG encryption. Perfect for local development, CI/CD pipelines, and ensuring your transactional emails actually deliver.