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

* [WildDuck Mail Server v1.51.4](https://github.com/zone-eu/wildduck) – Scalable IMAP/POP3 mail server designed without single points of failure, backed by sharded, replicated MongoDB.