* [Inbucket v3.2.0](https://github.com/inbucket/inbucket) – Disposable webmail server providing built-in SMTP, POP3, REST and web interfaces without requiring a database.

* [Mailpit v1.31.5](https://github.com/axllent/mailpit) – Small, fast, low memory email testing tool with an API for developers.

* [smtp-server v3.19.19](https://github.com/nodemailer/smtp-server) – Node.js module for creating SMTP and LMTP server instances dynamically.