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Mailu

Mailu is a free, open-source mail server packaged as Docker images, for admins who want to self-host email for their own domains.

Our take: Mailu takes much of the assembly work out of self-hosting email: one set of containers gives you mailboxes, webmail, an admin panel and the usual anti-abuse checks.

Best forSelf-hosted domain email
ReviewedPricing: Free
6.6 out of 105 criteria · see breakdown
Try MailuFree (MIT License); server costs extra

Mailu is a free, open-source mail server shipped as Docker images, for admins who want to host email for their own domains. It includes IMAP, SMTP, webmail, an admin interface, antispam and antivirus under the MIT License. The software costs nothing; you supply the server, a dedicated IP and the DNS setup.

The bottom line

A solid free choice if you already run Docker servers and want your own mail; others should pick hosted email.

Our score

Reviewed by the Conversion Gems editorial team. Hover a facet to focus it; click to pin.Tap a facet to focus it.

What it is, and why we rate it

One line each. Open a row for detail.

What it really isAn open-source mail server distribution that packages IMAP, SMTP, webmail, antispam and antivirus as Docker images.
Our takeMailu takes much of the assembly work out of self-hosting email: one set of containers gives you mailboxes, webmail, an admin panel and the usual anti-abuse checks.
It is free and still shipping fixes in 2026. What it cannot remove is the hard part of running mail, which is a clean IP, correct DNS and watching deliverability yourself.
Why we rate itFree, maintained and complete: mail, webmail, admin, antispam and antivirus without license fees.
The catchYou own deliverability, DNS, security patches and backups, with community support only.

Best / not good for

Best for
  • Self-hosting email for your own domains
  • Homelab and VPS users who know Docker
  • Small organizations that want data on their own server
Not good for
  • Anyone without a dedicated IP and reverse DNS
  • Teams that need vendor support or an SLA
  • Users who want email without running a server
Trade-offs

Friction report

Trade-offs to know before signing up.

  1. Time to value
    An hour or more for a first install if Docker and DNS are familiar; longer to get SPF, DKIM, DMARC and reverse DNS right.
  2. Scale breakpoint
    When you need high availability, vendor support or guaranteed deliverability.
  3. Walled garden
    None: standard IMAP and SMTP, MIT-licensed code, your data on your server.
Still a fit?
If none of these block you, start on the free plan.
Try Mailu

What you need to run Mailu

ItemRequirement
Memory (with antivirus)3GB RAM + 1GB swap
Memory (without antivirus)1GB RAM + 1GB swap
DeploymentDocker Compose v2 or Kubernetes
CPU architecturesamd64, arm64v8, armv7
Free ports on the host25, 80, 110, 143, 443, 465, 587, 993, 995, 4190
NetworkDedicated IP with forward and reverse DNS (highly recommended)
Software costFree (MIT License)

From Mailu's setup and requirements documentation for the 2024.06 branch, checked 4 October 2026.

Frequently Asked Questions

What is Mailu?

Mailu is an open-source mail server distributed as a set of Docker images. It bundles IMAP, SMTP, webmail, an admin interface, antispam and antivirus, so you can host email for your own domains on a server you control.

Is Mailu free?

Yes. Mailu is released under the MIT License and mailu.io offers no paid plan or hosted service (checked 4 October 2026). Your costs are the server, a dedicated IP address and your own time for setup and upkeep.

What do I need to run Mailu with Docker?

Mailu's requirements page asks for 3GB of memory and 1GB of swap with antivirus enabled, or 1GB of memory and 1GB of swap without it, plus Docker Engine and Docker Compose v2. Ports 25, 80, 110, 143, 443, 465, 587, 993, 995 and 4190 must be free, and a dedicated IP with forward and reverse DNS is highly recommended.

Is there a Mailu login or app?

Mailu has no central login because each install is self-hosted. You sign in to your own server's webmail and admin pages, and use any IMAP or SMTP mail app. To try it first, Mailu runs a public demo at test.mailu.io, which resets three times a day and cannot send mail outside the server.

Can Mailu run on a Raspberry Pi or ARM server?

Mailu publishes multi-arch images for linux/amd64, linux/arm64v8 and linux/armv7. The memory requirements still apply, so check that the device has 3GB of RAM if you want antivirus scanning.

Is Mailu still maintained?

Yes. The stable branch is 2024.06, and release 2024.06.61 was published on 30 September 2026. Older 1.x branches no longer get patches.

Mailu alternatives

Other ways to run email for your own domain:

Showing 1–3 of 3
Sources checked October 4, 2026: Mailu homepage, Mailu on GitHub, Mailu Compose requirements, Mailu setup guide, Mailu demo server, Mailu latest release.

Conversion Gems independently reviews every tool.

Tags

#SelfHosted#EmailServer#Docker#OpenSource

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