smtpd

OpenBSD Email Service

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

A reimplementation of the Python stdlib smtpd.py based on asyncio.

A Lightweight High Performance ESMTP email server

mxcheck is an info and security scanner for e-mail servers.

SMTP server (library) for receiving emails, written in pure PHP.

Blackhole is an MTA written on top of asyncio, utilising async and await statements that dumps all mail it receives to /dev/null.

SQLite-backed mail processing suite

Enable system-level AI agents on Android devices with on-device LLMs, secure tool control, and a conversational shell replacing the launcher

A Golang library for implementing RFC2821 SMTP servers

Gene's SMTP server — receive Internet mail with less fuss

Postmaster ESMTP server

Advanced SMTP penetration testing framework featuring AI-driven anomaly detection, 2026 CVE database, multi-threaded brute force, email harvesting, TLS certificate analysis, SPF/DKIM/DMARC validation, and interactive TUI. Gray hat tool for professional security assessments and bug bounty hunting.

Ansible role to install sendmail

Advanced SMTP Mail Sender with HTML warning themes, attachment support, and priority email options (v2 upgraded UI + bird-themed CLI).

A pytest fixture that creates an SMTP server.

A simple PHP wrapper for OpenBSD smtpd service to use in your web apps - PHP: <=8.1, GPL

A very basic simulation of a mail server storing mails received in an encrypted form. Originally developed as a mini project for Computer Networks, a subject taught in the 6th semester of B.E degree course in CS at PCCOE, Pune.

Simple SMTP daemon

SMTP servers and libraries like smtplib are used for email communication and development. Tools like smtp4dev help test email functionality, while SMTP checkers ensure proper relay configurations on Windows systems.