Smtp GitHub Repositories (2026) · Open Source Tools

MailCraft: an open-source, clean-room mail, calendar and contacts program in pure Rust, for Microsoft 365, Outlook.com and IMAP. Early alpha.

Hylki (formerly Vireo): a fast, GNOME-native email client built with Rust and libadwaita.

Self-hosted mail server for your own domain: SMTP/IMAP/POP3, CardDAV/CalDAV, React webmail and admin console, one-command Docker Compose.

An OOB interaction gathering server and client library

:mailbox: SMTP Server + Web Interface for viewing and testing emails during development.

High performance, self-hosted, newsletter and mailing list manager with a modern dashboard. Single binary app.

The first Open-Source high-performance MTA developed from the ground-up for high-volume email sending environments.

Built from the ground up for speed. Flectar Mail delivers native performance, instant startup, and about 20 MB of private memory at idle.

✉️ Composable all-in-one mail server.

A fast, highly extensible, and event driven SMTP server

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

Terminal-based email client for Linux and macOS

C/C++ server and network library, including coroutine,redis client,http/https/websocket,mqtt, mysql/postgresql/sqlite client with C/C++ for Linux, Android, iOS, MacOS, Windows, Harmony,etc..

mailcow: dockerized - 🐮 + 🐋 = 💕

📮 A fully featured open source mail delivery platform for incoming & outgoing e-mail

CLI to manage emails

All in one email sender for .NET. Supports popular senders (SendGrid, MailGun, etc) and Razor templates.

Disposable webmail server (similar to Mailinator) with built in SMTP, POP3, RESTful servers; no DB required.

Top geek's chindogu - personal assistant over satellite/telephone/SMS/chatbot, plus web infrastructure servers (web & mail, ad-free DNS, TCP-over-DNS, web proxy, etc)

💌 Mail app for Nextcloud