Top 21 webmail open source projects

Insular email distribution - mail server as Docker images

Open-source webmail script for existing IMAP server

An ad-hoc disposable temporary mail server. Create and use ad hoc disposable mailboxes for testing or any other purpose.

Isotope Mail Client

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.

Web based groupware server written in PHP, forum at https://help.egroupware.org/

poste.io mail server, but with IP management and custom webmail plugins

A secure and PGP enabled webmail module for Phosphorus Five

Lightweight webmail inspired by Gmail

Disposable webmail server (similar to Mailinator) with built in SMTP, POP3, RESTful servers; no DB required.

Cypht: Lightweight Open Source webmail written in PHP and JavaScript

💌 Mail app for Nextcloud

Self-hosted server for the ProtonMail client

AfterLogic WebMail Lite PHP. Fast and easy-to-use webmail front-end for your existing IMAP mail server, Plesk or cPanel.

Simple, modern & fast web-based email client

Monorepo hosting the proton web clients

A golang webmail server.

Application for Zimbra Email Service

Webmail front-end for existing mail server, with personal calendar, contacts, and mobile sync.

Mail Toaster 6

🌰️🐿️ SquirrelMail GitHub Repository (PHP 7-OK!)