The best open source alternative to Roundcube is Rainloop. If that doesn't suit you, our users have ranked more than 25 alternatives to Roundcube and many of them is open source so hopefully you can find a suitable replacement. Other interesting open source alternatives to Roundcube are Mailpile, Kolab, SOGo and Horde.
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.
Estonia
EU
Mailpile is a modern, fast web-mail client with user-friendly encryption and privacy features. The development of Mailpile is funded by a large community of backers and all code related to the project is and will be released under an OSI approved Free Software license.
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.
Canada
Enterprise-level, browser-based suite for IMAP email, calendar, contacts, tasks, notes, wiki, and file management, offering syncing, shared and unlimited resources, multilingual support, customizable dashboard, and integration with mobile and external clients.
United States
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.
GermanyEU
Cloudflare Workers-based email solution providing multiple address generation, attachment storage via R2, responsive web interface, RBAC management, Resend bulk email, Telegram or third-party forwarding, verification code recognition, and ECharts analytics.
China
The drastically upgraded & secured fork of RainLoop Webmail Community edition.
NetherlandsEU
All your E-mail, from all your accounts, in one place. Cypht is like a news reader, but for E-mail. Cypht does not replace your existing accounts - it combines them into one. And it's also a news reader :).
United States
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.
Pakistan
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.
United States
Switzerland
