Open-source Axigen alternatives

Docker Mailserver runs a complete mail server inside a container. It bundles SMTP and IMAP services (Postfix and Dovecot, according to the project topics), optional LDAP authentication, and anti-spam and anti-virus tooling, so a self-hoster does not have to assemble each piece separately.

The design is deliberately simple: it uses configuration files only, with no SQL database, which keeps setups easy to version, deploy and upgrade. Related topics include fail2ban and Rspamd. The documentation covers initial setup, environment variables, updating and an FAQ, and the project asks users to match the documentation version to the image version they run.

Docker Mailserver is released under the MIT license and has been maintained by volunteers since January 2021. It is a self-hosting project with no hosted offering, suited to administrators who want to run their own mail on a server they control.

Mail-in-a-Box helps individuals take back control of their email by providing a one-click, easy-to-deploy mail server in a box. It turns a fresh Ubuntu 22.04 LTS 64-bit machine into a working mail server by installing and configuring the required components. There are no user-configurable setup options, so it is designed to just work.

The installed components include Postfix for SMTP, Dovecot for IMAP, Nextcloud for CardDAV and CalDAV, z-push for Exchange ActiveSync, and Roundcube webmail. It adds spam filtering with SpamAssassin and greylisting with Postgrey, DNS with SPF, DKIM, DMARC, DNSSEC, DANE TLSA, MTA-STS and SSHFP records set automatically, and TLS certificates from Let's Encrypt. Backups use duplicity, with ufw, fail2ban and munin for protection and monitoring.

Project goals include making a good mail server easy to deploy, promoting decentralization and privacy, and keeping configuration automated, auditable and idempotent. It deliberately does not aim to be customizable by power users. Mail-in-a-Box is written in Python, released into the public domain under CC0-1.0, and has a Code of Conduct for contributors.

Stalwart is an open-source mail and collaboration server written in Rust and designed to be secure, fast, robust and scalable. It supports JMAP, IMAP4, POP3, SMTP, CalDAV, CardDAV and WebDAV, so a single server can handle email, calendars, contacts and file storage.

On the email side it offers JMAP for Mail and Sieve, IMAP4rev2 and IMAP4rev1 with ManageSieve, and POP3. The SMTP server includes DMARC, DKIM, SPF and ARC for message authentication, transport security through DANE, MTA-STS and TLS reporting, automated DKIM key rotation, throttling and filtering rules, sieve scripting and milter integration, and distributed virtual queues.

The collaboration features cover CalDAV and JMAP for Calendars, CardDAV and JMAP for Contacts, and WebDAV and JMAP for File Storage, with fine-grained sharing through WebDAV ACL and JMAP Sharing. A built-in spam and phishing filter includes a rule set and LLM-driven message analysis. It is self-hosted software that administrators run on their own servers.

mailcow: dockerized is an open-source mail server package that runs as a set of Docker containers managed with Docker Compose. It bundles the pieces needed to run your own email, so administrators do not have to assemble and configure each component separately.

The stack is built around established open-source software: Postfix for SMTP, Dovecot for IMAP, Rspamd for spam filtering, ClamAV for antivirus scanning, SOGo for groupware and webmail, and ACME support for certificates. A web administration interface sits on top. Topics in the repository also mention the Olefy component for document scanning.

mailcow is released under the GNU General Public License v3 and installed on your own server following the official documentation. It is managed and maintained by The Infrastructure Company GmbH, and the project offers support contracts through Servercow as well as a one-time support payment option. The community gathers on Telegram, Mastodon and GitHub Sponsors.

Mailu is a full-featured mail server delivered as a set of Docker images. The project aims to give people an easily set up and maintained mail server made entirely of free software, without proprietary components or unrelated groupware features and without trackers.

It covers the standard email server functions, IMAP and SMTP with client auto-configuration profiles, along with aliases, domain aliases, custom routing and full-text search of attachments. Users get webmail, auto-reply, auto-forward and managesieve, while admins get global admin roles, per-domain delegation, announcements and quotas. Security features include enforced TLS, DANE, MTA-STS, Let's Encrypt certificates, outgoing DKIM and an antivirus scanner, and antispam features include greylisting, auto-learning, DMARC, SPF and anti-spoofing checks.

Mailu is written in Python and deployed with Docker or Docker Compose. The project's own configuration files, Dockerfiles and code are MIT-licensed, and all bundled components are free software compatible with it. A demo server and website documentation are provided.

Modoboa is an open-source email server that comes with a modern web interface for administration. Its pitch is that running your own mail server should not require deep technical knowledge: the project says setup takes under ten minutes. It positions itself against paid mailboxes from internet providers, free webmail services that monetize your data, and doing everything by hand.

Under the hood it brings together established open-source components, including Postfix, Dovecot and Rspamd, behind a single interface. The resulting server offers the usual hosting features: webmail, calendars, address books, filtering rules to organize messages, an auto-responder, and unlimited domains, mailboxes and aliases. An administration panel covers managing all of these.

Modoboa is written in Python with Django and a Vue front end, and it is released under the ISC license. You host it yourself, which suits small businesses, associations and individuals who want control over their email and privacy. The website also lists a Modoboa Pro offering and a sponsoring page for supporting development.

SOGo is an open-source groupware suite that combines calendaring, address book management and a full webmail client, along with resource sharing and permission handling. It is described as fast and scalable, and it is written mainly in Objective-C with an AngularJS Material web interface. It is licensed under GPL-2.0 and developed by Alinto.

Because SOGo relies on documented standards such as IMAP, CalDAV and CardDAV, it provides native connectivity without plugins to many clients, including Microsoft Outlook, Apple iCal, the iPhone, Mozilla Lightning and many mobile devices. A Thunderbird connector extension for Thunderbird 78 and later is available in a separate repository.

Building SOGo requires the source of both SOGo and SOPE, the underlying application server framework, and a FAQ covers compilation. A dev container is available for development. The project welcomes documentation work, feature requests, mailing list participation, patches and translations, and the README lists official translations in many languages with their maintainers.