Mailu

Against what buyers need

Email server: covers 82% of the checklist. A set of Docker images with Rspamd, an optional virus scanner, DKIM signing, a choice of Roundcube or SnappyMail webmail and an admin UI for domains, aliases and users, plus auto-reply, forwarding and ManageSieve. It is lighter than mailcow but has no ActiveSync, calendars only through the optional Radicale WebDAV service, and directory login only through header authentication behind an external identity provider. Missing: end-to-end or PGP encryption and high-volume sending.

Judgement

What it is

Complete system

What it does

A complete mail server shipped as Docker images, with SMTP, IMAP, webmail, an admin interface, antispam, antivirus and DKIM signing.

Adopt it when

You want to host email for a few domains on your own server and prefer a Docker Compose setup with a web admin over assembling Postfix and Dovecot by hand.

Watch out

Running any mail server means owning IP reputation and deliverability, and Mailu releases come only about once a year.

Ready for

Production-ready

Runs as

Self-hosted server

Built with

Python, Postfix, Dovecot, Rspamd and Docker

How established

Established: started 10 years ago, latest release 2024.06.67.

What the license allows

GitHub could not read the license. Check it in the repository before reusing any code.

Judged on 2026-11-06 from the project's README and GitHub data. The license and age lines are worked out directly.

Built from

Follow it down: Mailu → CPython → GCC → LLVM project → runs on a microchip

How compilers were built, back to punched paper tape

Open-source alternatives to Mailu

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3. 3
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