Open-source email servers and webmail in 2026
22 open-source projects, ranked by GitHub stars and how recently each was worked on. Docker Mailserver leads with 20k stars, ahead of Mailcow-dockerized. 17 had code pushed in the last three months. Most common licenses: MIT (7), AGPL-3.0 (6) and GPL-3.0 (5). Commercial email servers and webmail are listed separately.
New this season
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1
OpenInbox sums001
Free, unlimited business email on your own domains, running entirely in your free Cloudflare account.
Complete system Experimental A small business already on Cloudflare wants free mailboxes for several domains and can tolerate beta software on a spare domain first.
★ 105 MIT TypeScript Active, pushed yesterday -
2
Mailez mailez-hq
Self-hosted mail server for your own domain: SMTP/IMAP/POP3, CardDAV/CalDAV, React webmail and admin console, one-command Docker Compose.
Complete system Experimental You want an all-in-one mail server with modern webmail and are prepared to test a very new project thoroughly first.
★ 294 AGPL-3.0 Go Active, pushed 20 days ago -
3
OpenMail chenyuwebwawa
A self-hosted, open-source mail server suite in a single Node.js process — full-stack email with SMTP / IMAP / POP3, a modern three-pane webmail, an admin dashboard, multi-tenancy, DKIM, anti-spam and 2FA. Zero native dependencies, one SQLite file, up and running in minutes.
Complete system Experimental You want to experiment with a single-process mail server on a test domain.
★ 116 MIT JavaScript Active, pushed 13 days ago -
4
OmniMail mibgb65-cloud
Self-hosted multi-domain webmail on Cloudflare Workers, D1, R2, Queues, Email Routing, and Resend.
Complete system Experimental An individual or small team on Cloudflare wants serverless webmail for several domains without running a mail server.
★ 271 MIT TypeScript Active, pushed 17 days ago
All open-source email servers and webmail, ranked
Complete systems you can adopt 19
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1
Docker Mailserver docker-mailserver
Production-ready fullstack but simple mail server (SMTP, IMAP, LDAP, Antispam, Antivirus, etc.) running inside a container.
Complete system Production-ready You want a simple self-hosted mail server without a web admin panel.
★ 20k MIT Shell Active, pushed today -
2
Mailcow-dockerized mailcow
mailcow: dockerized - 🐮 + 🐋 = 💕
Complete system Production-ready You want to host email for several domains yourself with a full admin interface.
★ 14k GPL-3.0 JavaScript Active, pushed yesterday -
3
Roundcubemail roundcube
The Roundcube Webmail suite
Complete system Production-ready You run an IMAP server and need a dependable webmail front end.
★ 7.3k GPL-3.0 PHP Active, pushed 8 days ago -
4
WebClients ProtonMail
Monorepo hosting the proton web clients
Complete system Production-ready You want to audit or contribute to Proton's client code; to use Proton, sign up for the hosted service.
★ 5.7k GPL-3.0 TypeScript Active, pushed today -
5
Cypht cypht-org
Cypht: Lightweight Open Source webmail aggregator [PHP, JS]. Supports IMAP/SMTP, JMAP and EWS (Exchange Web Services)
Complete system Production-ready You want a lightweight self-hosted webmail that aggregates mailboxes from different providers.
★ 1.8k LGPL-2.1 PHP Active, pushed today -
6
MailFlow maathimself
A self-hosted, unified webmail client.
Complete system Usable You juggle several mail accounts and want one self-hosted web interface for them.
★ 628 AGPL-3.0 JavaScript Active, pushed today -
7
KumoMTA KumoCorp
The first Open-Source high-performance MTA developed from the ground-up for high-volume email sending environments.
Complete system Production-ready You send millions of emails and want an open alternative to commercial MTAs such as PowerMTA.
★ 571 Apache-2.0 Rust Active, pushed 4 days ago -
8
Webmail-lite-8 afterlogic
Open-source webmail script for existing IMAP server
Complete system Production-ready A host or small company wants a free webmail front end on its own IMAP server, maintained by a commercial vendor.
★ 363 AGPL-3.0 Shell Active, pushed 7 days ago -
9
Mailez mailez-hq
Self-hosted mail server for your own domain: SMTP/IMAP/POP3, CardDAV/CalDAV, React webmail and admin console, one-command Docker Compose.
Complete system Experimental You want an all-in-one mail server with modern webmail and are prepared to test a very new project thoroughly first.
★ 294 AGPL-3.0 Go Active, pushed 20 days ago -
10
OmniMail mibgb65-cloud
Self-hosted multi-domain webmail on Cloudflare Workers, D1, R2, Queues, Email Routing, and Resend.
Complete system Experimental An individual or small team on Cloudflare wants serverless webmail for several domains without running a mail server.
★ 271 MIT TypeScript Active, pushed 17 days ago -
11
JMAP webmail root-fr
Modern JMAP webmail client built for Stalwart Mail Server. Privacy-focused, responsive, with real-time updates.
Complete system Usable You run Stalwart and want a modern webmail designed for it.
★ 236 MIT TypeScript Active, pushed 43 days ago -
12
Gofer cristianadrielbraun
Self-hosted multi-account email client with support for JMAP/IMAP/SMTP, direct integration with Gmail and Outlook APIs. Also Contacts and Calendar. Built with Go, templ, and HTMX, SQLite for storage
Complete system Usable You want one self-hosted interface for personal mail across providers and can live with pre-1.0 changes.
★ 169 MIT Go Active, pushed today -
13
LanQin Email LanQin996
自托管邮件系统，提供现代化 Webmail 与管理后台，支持多域名、外部 IMAP、邮箱共享、细粒度权限和简繁英三语言。
Complete system Experimental A Chinese-speaking organisation wants a single-container mail server with a modern admin interface.
★ 167 GPL-3.0 Go Active, pushed 3 days ago -
14
OpenMail chenyuwebwawa
A self-hosted, open-source mail server suite in a single Node.js process — full-stack email with SMTP / IMAP / POP3, a modern three-pane webmail, an admin dashboard, multi-tenancy, DKIM, anti-spam and 2FA. Zero native dependencies, one SQLite file, up and running in minutes.
Complete system Experimental You want to experiment with a single-process mail server on a test domain.
★ 116 MIT JavaScript Active, pushed 13 days ago -
15
OpenInbox sums001
Free, unlimited business email on your own domains, running entirely in your free Cloudflare account.
Complete system Experimental A small business already on Cloudflare wants free mailboxes for several domains and can tolerate beta software on a spare domain first.
★ 105 MIT TypeScript Active, pushed yesterday -
16
Magma lavabit
The magma server daemon, is an encrypted email system with support for SMTP, POP, IMAP, HTTP and MOLTEN,. Additional support for DMTP and DMAP is currently in active development.
Complete system Experimental You are researching encrypted mail protocols; it is not a practical choice for running a mail service.
★ 1.8k AGPL-3.0 C Quiet, pushed 2 years ago -
17
Mailur naspeh
Lightweight webmail inspired by Gmail
Complete system Experimental Only if you want to revive a tag-based webmail; there are maintained alternatives.
★ 788 GPL-3.0 Python Quiet, pushed 4 years ago -
18
WebMail Lite afterlogic
AfterLogic WebMail Lite PHP. Fast and easy-to-use webmail front-end for your existing IMAP mail server, Plesk or cPanel.
Complete system Experimental Do not adopt this repository; Afterlogic's maintained version is WebMail Lite 8.
★ 455 AGPL-3.0 PHP Quiet, pushed 7 years ago -
19
Isotope Mail manusa
Isotope Mail Client
Complete system Experimental Only as a code reference; the author calls it very early stage.
★ 242 Apache-2.0 JavaScript Quiet, pushed 4 years ago
Integrations 1
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1
Nextcloud Mail nextcloud
💌 Mail app for Nextcloud
Integration Production-ready Your team works in Nextcloud and wants email in the same interface as files and calendar.
★ 1.1k AGPL-3.0 JavaScript Active, pushed today
Developer tools 2
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1
Ad-Hoc-Email-Server o4oren
An ad-hoc disposable temporary mail server. Create and use ad hoc disposable mailboxes for testing or any other purpose.
Developer tool Usable You need many throwaway mailboxes for testing or for sign-ups you expect to attract spam.
★ 412 Apache-2.0 TypeScript Slowing, pushed 7 months ago -
2
Rapid-Inbox wendaochangsheng
Self-hosted inbound email infrastructure with a high-performance C++ SMTP ingestion engine, local storage, and developer APIs.
Developer tool Experimental You need throwaway inboxes for testing sign-up and notification emails in automated tests.
★ 128 MIT Python Active, pushed 3 months ago
Compared head to head
Looking for an alternative to
Open-source licenses
- Permissive: 10. Use it anywhere, including in closed products. You keep the copyright notice; Apache-2.0 also grants patent rights.
- Network copyleft: 6. Like GPL, and running a changed version as a web service counts as distributing it, so its users get the source too.
- Strong copyleft: 5. If you distribute the program or anything built on it, you must release the whole source under the same license.
- Weak copyleft: 1. Changes to the licensed files must be shared, but you can link them into a closed program.
Languages
JavaScript 5, TypeScript 5, PHP 3, Go 3, Shell 2, Python 2, Rust 1 and C 1.
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