Mailu

Mailu is a self-hosted mail server built entirely from free and open-source components, deployed as a Docker Compose stack. Where tools like Mail-in-a-Box target first-time mail server operators with heavy automation, Mailu is aimed at administrators who want more control over their configuration without building the stack component by component.

A single Docker Compose file brings up the full email stack: SMTP with DKIM, DMARC, and SPF, IMAP with full-text search, an admin interface, anti-spam (Rspamd), anti-virus (ClamAV), and your choice of webmail (Roundcube or Snappymail). Let’s Encrypt certificate handling is built in.

The admin panel covers domain management, user accounts, aliases, and quotas without touching config files directly. Per-domain delegation lets different admins manage different domains on the same installation, which matters for hosting multiple organizations on shared infrastructure.

Mailu is MIT-licensed and free. The setup process involves generating a compose file through a web-based wizard, which produces a configuration tailored to your domain and storage choices.

The main operational consideration with any self-hosted mail server applies here too: IP reputation and correct DNS setup (SPF, DKIM, DMARC, reverse DNS) determine whether your mail reaches inboxes reliably. For teams that want a full-featured, maintainable mail server without assembling it from individual parts, Mailu is one of the more approachable options available.