Stalwart is an open-source mail & collaboration server with JMAP, IMAP4, POP3, SMTP, CalDAV, CardDAV and WebDAV support and a wide range of modern features. It is written in Rust and designed to be secure, fast, robust and scalable. Stalwart Labs' mission is to help modernize, democratize and promote decentralization of email by creating an open-source mail server in Rust that is simple to run but at the same time extremely secure, robust and focused on privacy.