- [Dovecot](https://www.dovecot.org/) - IMAP and POP3 server written primarily with security in mind. ([Source Code](https://github.com/dovecot/core)) `MIT/LGPL-2.1``C/deb`
- [MailForm](https://github.com/Feuerhamster/mailform) - Lightweight self-hosted email service for contact forms and more (alternative to Formspree and SendGrid). `Apache-2.0``Nodejs/Docker`
- [Stalwart JMAP](https://stalw.art/jmap) - JMAP and IMAP server designed to be secure, fast, robust and scalable. ([Source Code](https://github.com/stalwartlabs/jmap-server)) `AGPL-3.0``Rust/Docker`