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.
Roundcube vs Squirrelmail opinions
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.
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.Discontinued
1.0.0 Release Candidate 6 from 2019 is the last version on GitHub (https://github.com/mailpile/Mailpile/releases). Possibly the development has been stopped.
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.
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.
The last release (5.2.22) was in September 2017.
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.This app doesn't have any features at the moment.
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 :).
Microservice based webmail client built with ReactJS and Spring.
Minimalistic webmail client which currently has the main features of any other mail client (read mail, compose mail, organize mail folders...).
Turing Email is an email client that you can use with your existing email accounts that is packed with innovative features packaged into a beautiful design.