Roundcube Alternatives for Online

Mailpile is a free and open-source webmail client designed with privacy and encryption as core principles. It offers a self-hostable solution for managing your email with built-in support for PGP encryption and other security features, providing an alternative to traditional webmail services.

Kolab Community is a comprehensive, free, and open-source groupware suite designed for collaborative work. It provides integrated email, calendar, contacts, and tasks functionalities, empowering individuals and teams to communicate and manage their data efficiently and with a strong focus on data privacy.

Zimbra Collaboration Suite is a comprehensive open source email and collaboration platform designed for businesses. It provides a secure and feature-rich environment for email, calendaring, contacts, tasks, and file sharing, supporting on-premises and cloud deployments.

Horde Groupware is a free, web-based suite of applications designed for collaboration and productivity. Built on the robust Horde framework, it offers a comprehensive set of tools including webmail, calendar, task management, and note-taking, providing an integrated platform for individuals and teams.

Webmail Lite is an open-source, self-hosted webmail client designed for individuals and businesses seeking a private and customizable email solution. It offers basic email functionalities with a focus on privacy and control.

OX Open-Xchange is a comprehensive web-based suite designed for communication, collaboration, and office productivity, offering features like email, calendaring, task management, and document sharing, seamlessly integrating across devices.