18 self-hosted IceWarp alternatives

Production-ready mail server stack in a Docker container with SMTP, IMAP/POP3, LDAP auth, anti-spam/AV, DKIM/DMARC, and optional OAuth2 support.

18.6k stars2k forksMITlast commit 18 Jul 2026Actively maintained

Mail-in-a-Box is a one-click mail server appliance for Ubuntu, bundling SMTP/IMAP, webmail, DNS, TLS automation, backups, and an admin control panel.

15.4k stars1.5k forksCC0-1.0last commit 24 May 2026Actively maintained

All-in-one open-source mail and collaboration server with SMTP, IMAP, JMAP, CalDAV, CardDAV, and WebDAV, plus integrated anti-spam and phishing protection.

13.9k stars848 forkslast commit 27 Jul 2026Actively maintained

Mailcow is a dockerized mail server suite providing SMTP/IMAP, webmail, anti-spam/anti-virus, and domain/mailbox administration via a unified web UI.

13.2k stars1.8k forksGPL-3.0last commit 15 Jul 2026Actively maintained

Mailu is a full-featured mail server distributed as Docker images, providing SMTP/IMAP/POP3, webmail, administration UI, and built-in security and anti-spam features.

7.4k stars990 forkslast commit 26 Jul 2026Actively maintained

All-in-one secure mail server with SMTP, IMAP, webmail, automatic TLS (ACME), and built-in SPF/DKIM/DMARC plus junk filtering for low-maintenance domains.

5.8k stars210 forksMITlast commit 20 Jul 2026Actively maintained

Modoboa is an open source mail server management platform with a modern web UI, integrating Postfix and Dovecot with admin tools, webmail, calendar, and address book.

3.5k stars476 forksISClast commit 27 Jul 2026Actively maintained

A Bash script that auto-implements a full mail server (Postfix, Dovecot, DKIM, SpamAssassin) with TLS and PAM-based logins on Debian/Ubuntu.

2.2k stars340 forksGPL-3.0last commit 4 May 2025Slowing down

Automated open-source mail server installer bundling Postfix, Dovecot, webmail, anti-spam/antivirus and LDAP/SQL backends for mainstream Linux/BSD.

1.8k stars259 forksGPL-3.0last commit 22 Jul 2026Actively maintained

High-performance, standards-compliant IMAP/POP3/LMTP server with flexible authentication, extensible plugin system (Lua, Sieve) and OpenSSL TLS support.

1.2k stars345 forkslast commit 24 Jul 2026Actively maintained

Cyrus IMAP is a secure, scalable mail server providing IMAP/JMAP email plus CalDAV/CardDAV contacts and calendars, with ACLs, quotas, search, and replication.

637 stars173 forkslast commit 27 Jul 2026Actively maintained

Open-source PHP groupware providing CalDAV/CardDAV, ActiveSync, email client, CRM, tasks, file manager and Docker images for on-premise collaboration.

21 stars5 forksAGPL-3.0last commit 27 Jul 2026Actively maintained

Open-source webmail and groupware offering email, contacts, calendar, cloud drive, tasks, notes and an admin control panel for multi-tenant email services.

Activity unknown

Citadel is an open source groupware and messaging server providing email, calendars, contacts, and a web interface with room-based collaboration.

Activity unknown

WikiSuite is an integrated open source suite combining wiki/groupware, chat and conferencing, webmail, search, and infrastructure management for organizations.

Activity unknown

Courier is an integrated mail server suite providing ESMTP (MTA), IMAP, POP3, webmail, and mailing lists with optional LDAP/MySQL/PostgreSQL-backed virtual accounts.

Activity unknown

Simple NixOS Mailserver provides NixOS modules to deploy a full email server with SMTP/IMAP, spam filtering, DKIM/DMARC/SPF, and TLS automation.

Activity unknown

Self-hosted enterprise collaboration suite providing email, webmail, calendaring, contacts, and administration for organizations.

Activity unknown