* [Cloud Mail v3.0.0](https://github.com/maillab/cloud-mail) – Serverless email platform built on Cloudflare Workers with web and API support.

* [Cloud Mail v3.0.0](https://github.com/eoao/cloud-mail) – Cloudflare Workers-based email service offering web UI, D1/KV/R2 storage, and Resend integration.

* [MailTime 4.0.0](https://github.com/veliovgroup/mail-time) – Email queuing system that extends Nodemailer with multi-SMTP rotation, storage-backed retries, and horizontal scaling support.

* [Mailspring 1.21.0](https://github.com/Foundry376/Mailspring) – Beautiful, fast mail client for managing emails across multiple platforms.

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

* [enmime v2.4.0](https://github.com/jhillyerd/enmime) – MIME encoding and decoding library for Go, focused on generating and parsing MIME-encoded email messages.

* [Mailtrap Node.js client v4.6.0](https://github.com/mailtrap/mailtrap-nodejs) – Node.js client for sending transactional and bulk emails with sandbox mode, attachments, and API token-based authentication.

* [Maddy Mail Server v0.9.5](https://github.com/foxcpp/maddy) – Composable all-in-one mail server implementing SMTP (MTA/MX), IMAP storage, and security protocols such as DKIM, SPF, DMARC, and DANE.

* [go-mail v0.7.3](https://github.com/wneessen/go-mail) – Easy-to-use, comprehensive library for sending email via SMTP with Go.

* [mails v1.5.6](https://github.com/chekusu/mails) – Email infrastructure for AI agents to send, receive, search, and parse emails programmatically.