Roundcube is an open-source, self-hosted webmail client designed for reading, composing, and organizing emails stored on remote servers using IMAP and SMTP protocols. It provides a browser-based interface that allows users to manage their mailboxes and sender identities through a secure communication platform.
The platform is distinguished by its modular architecture, featuring a plugin-based extension system for adding new functional modules and a skin-based theme layer for customizing the visual appearance and responsive layouts. It further supports embedding its interface into external cloud productivity suites and collaborative workspaces using single sign-on.
Core capabilities include encrypted email communication, collaborative address book management via directory connectors, and advanced message organization using threaded listings and global search. The system incorporates security measures such as two-factor authentication, brute-force prevention, HTML content sanitization, and shared folder access control lists.
The software includes built-in tools for mailbox data import and export, as well as scripts for configuration migration during system upgrades.