* [MailTime 4.1.0](https://github.com/veliovgroup/mail-time) – Email queuing system that extends Nodemailer with multi-SMTP rotation, storage-backed retries, and horizontal scaling support.

* [smtp-server v3.18.5](https://github.com/nodemailer/smtp-server) – Node.js module for creating SMTP and LMTP server instances dynamically.