* [Postal 3.3.7](https://github.com/postalserver/postal) – Fully featured mail delivery platform for incoming and outgoing email, designed for self-hosted deployment.

* [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.

* [go-premailer v1.34.0](https://github.com/vanng822/go-premailer) – Inlines CSS into HTML email for Go.