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Reviewed · Updated 2026-10-04

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.

Reviewed by the Conversion Gems editorial team ·
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Pricing
Free
Best for
Self-hosted domain email
Category
Hosting Providers

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.

6.6
Our score
6.6 / 10
Conversion Gems editorial verdict
Free (MIT License); server costs extra
Features7/10
7 - IMAP, SMTP, webmail, admin UI, antispam, antivirus, DKIM, DANE, MTA-STS and a REST API, per the README; no groupware such as shared calendars is listed.
Value9/10
9 - free under the MIT License with no paid tier; only server and IP costs apply.
Ease of use4/10
4 - needs Docker Compose v2, 3GB RAM with antivirus, free mail ports, a dedicated IP and DNS records, per the requirements page.
Ecosystem6/10
6 - standard IMAP and SMTP for any client, a REST API and CLI, Docker and Kubernetes deployments; few packaged integrations.
Support5/10
5 - versioned docs, GitHub issues and a Matrix chat room; no paid or live vendor support.
What it really is

An open-source mail server distribution that packages IMAP, SMTP, webmail, antispam and antivirus as Docker images.

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. 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 it

Free, maintained and complete: mail, webmail, admin, antispam and antivirus without license fees.

The catch

You own deliverability, DNS, security patches and backups, with community support only.

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
Friction report
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.
Scale breakpoint
When you need high availability, vendor support or guaranteed deliverability.
Walled garden
None: standard IMAP and SMTP, MIT-licensed code, your data on your server.

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

Mailu alternatives

Other ways to run email for your own domain:

SmarterMail: Commercial mail and groupware server for Windows Server, Linux or Docker, with a small free edition.
Migadu: Hosted email for your domains, so there is no mail server to maintain.
Amazon SES: AWS email service for sending and receiving through your own domains via API or SMTP, without full mailboxes.
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Tags

#SelfHosted#EmailServer#Docker#OpenSource

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