jstedfast / MailKit

A cross-platform .NET library for IMAP, POP3, and SMTP.

bbottema / simple-java-mail

Simple API, Complex Emails (Jakarta Mail smtp wrapper)

hkdb / aerion

An Open Source Lightweight E-Mail Client

xhit / go-simple-mail

Golang package for send email. Support keep alive connection, TLS and SSL. Easy for bulk SMTP.

thehijacker / hmelj

Self-hosted webmail client for IMAP/SMTP, Microsoft 365 and Exchange. Multi-account, multi-user, PWA + Android app.