Open Source WebMail Providers

Secure Swiss-based email with end-to-end encryption and zero third-party access. Available across devices, offering a free version to promote privacy.

End-to-end encrypted app for email, calendar, and contacts, requiring no personal data, with open source code and quantum-resistant security.

Disroot is a platform providing online services based on principles of freedom, privacy, federation and decentralization.

Web- and IMAP-based email service. 2GB cost 1€/month. Information is hosted on encrypted hard drives. Electricity from renewable resources is used.

Roundcube webmail is a browser-based multilingual IMAP client with an application-like user interface. It provides full functionality you expect from an e-mail client, including MIME support, address book, folder manipulation, message searching and spell checking.

Privacy-friendly Swiss email solution with 20 GB free storage, custom domain options, contact and calendar sync, and cross-device access in a secure suite.

A/I provides tools for anonymous communication and sharing. We recommend to use our services along with some specific personal privacy protection tool

Simple, modern & fast web-based email client. Modest system requirements, decent performance, simple installation and upgrade, no database required. All these make RainLoop Webmail a perfect choice for your email solution.

SOGo is groupware server with a focus on scalability and open standards.

SOGo provides a rich AJAX-based Web interface and supports multiple native clients through the use of standard protocols such as CalDAV, CardDAV and GroupDAV.Share your calendars, address books and mails in.

The power of simplicity. Onion Mail can manage emails in the normal network and in the Tor. Onion Mail protect your privacy and anonymity.

Inboxkitten is an open-source disposable email service that you can freely deploy adopt on your own!

Zero is an open-source AI email solution that gives users the power to self-host their own email app while also integrating external services like Gmail and other email providers. Our goal is to modernize and improve emails through AI agents to truly modernize emails.

NexMail is an open-source, modern webmail client designed for self-hosted email servers. Enjoy a clean, intuitive interface with powerful features for managing your emails efficiently.

Kolab Now provides a suite of intuitive apps in a user friendly environment to make your day to day online comms easier, smarter and most importantly; secure.

Horde Groupware is a free, enterprise ready, browser based collaboration suite. Users can manage and share calendars, contacts, tasks and notes with the standards compliant components from the Horde Project.

Anonymous peer-to-peer distributed communication layer built with open source tools and designed to run any traditional Internet service such as email, IRC or web hosting.

SquirrelMail is a standards-based webmail package written in PHP. It includes built-in pure PHP support for the IMAP and SMTP protocols, and all pages render in pure HTML 4.0 (with no JavaScript required) for maximum compatibility across browsers.

Open Source WebMail Lite is a free community edition of full-featured WebMail Pro server application intended for users who need a clean and simple web mail application, which is fast and easy to use. Whether you need a free web browser based email client software for Windows ASP.

Swisscows.email is another product of Swisscows AG. This product offers you secure email traffic. With Swisscows.email you can send your emails encrypted so that absolutely no one can read them. The service is comparable to a letter that is protected from prying eyes in an...

The OX App Suite by Open-Xchange is web-based platform offering a suite of apps like an email client, calendar, contacts magement, cloud storage with synchronization and productivity apps for word processing, spreadsheets and presentations.

Self-hosted server for the Proton Mail client.

Open Source standalone trashmail solution that ships its own mail server.

Is a collaboration suite (messaging and groupware). It is designed to run on open source operating systems such as Linux or BSD. In order to modernize the Citadel platform for the Internet, the Citadel/UX developers added functionality such as shared calendars, instant...

Modoboa is a mail hosting and management platform including a modern and simplified Web User Interface. It provides useful components such as an administration panel or a webmail.

OBM is a free messaging and collaboration platform useful for just a couple to many thousands of users with strong support for mobile devices.