Best self-hosted Communication - Email - Mail Transfer Agents software in 2026

Mail Transfer Agents (MTAs) - SMTP servers.

We track 9 open-source, self-hosted Communication - Email - Mail Transfer Agents apps. 3 of them had commits in the last 90 days, 0 can run with Docker, and the most common licenses are GPL-3.0 (3), MIT (1), ISC (1). The most-used languages are C, Nodejs, Go. Below are the top picks by GitHub stars, followed by every app ranked by stars weighted by maintenance health.

Alternatives to Brevo Alternatives to SendGrid Alternatives to Mailgun Alternatives to Amazon SES Alternatives to Postmark

Top 3 by GitHub stars

#	App	Stars	Health	Last activity	License	Language	Docker
1	Haraka	5.6k	Active	2026-11-06	MIT	Nodejs	–
2	OpenSMTPD	587	Active	2026-11-03	ISC	C, deb	–
3	DragonFly	266	Active	2026-08-30	BSD-3-Clause	C	–

Haraka — Fast, highly extensible, and event driven SMTP server.
OpenSMTPD — Secure SMTP server implementation from the OpenBSD project.
DragonFly — Small MTA for home and office use. Works on Linux and FreeBSD.

Head-to-head comparisons

Haraka vs OpenSMTPD DragonFly vs Haraka DragonFly vs OpenSMTPD

All 9 self-hosted Communication - Email - Mail Transfer Agents apps

Ranked by GitHub stars weighted by maintenance health.

Haraka

Fast, highly extensible, and event driven SMTP server.

Active ★ 5.6k MIT ~$5/mo

OpenSMTPD

Secure SMTP server implementation from the OpenBSD project.

Active ★ 587 ISC ~$3.5/mo

DragonFly

Small MTA for home and office use. Works on Linux and FreeBSD.

Active ★ 266 BSD-3-Clause ~$3.5/mo

chasquid

SMTP (email) server with a focus on simplicity, security, and ease of operation.

Unknown Apache-2.0 ~$3.5/mo

Courier MTA

Fast, scalable, enterprise mail/groupware server providing ESMTP, IMAP, POP3, webmail, mailing list, basic web-based calendaring and scheduling services.

Unknown GPL-3.0 ~$3.5/mo

EmailRelay

Small and easy to configure SMTP and POP3 server for Windows and Linux.

Unknown GPL-3.0 ~$3.5/mo

Exim

Message transfer agent (MTA) developed at the University of Cambridge.

Unknown GPL-3.0 ~$3.5/mo

Postfix

Fast, easy to administer, and secure Sendmail replacement.

Unknown IPL-1.0 ~$3.5/mo

Sendmail

Message transfer agent (MTA).

Unknown Sendmail ~$3.5/mo

Frequently asked questions

What is the best self-hosted Communication - Email - Mail Transfer Agents software in 2026?

By GitHub stars, the most popular self-hosted Communication - Email - Mail Transfer Agents apps are Haraka (5,635 stars), OpenSMTPD (587 stars), DragonFly (266 stars). Popularity is only one signal: also check maintenance health, license and whether it fits your setup.

How many self-hosted Communication - Email - Mail Transfer Agents apps are actively maintained?

3 of the 9 apps listed had commits in the last 90 days; for 6 we have no repository activity data.

Which licenses do self-hosted Communication - Email - Mail Transfer Agents apps use?

The most common licenses in this category are GPL-3.0 (3 apps), MIT (1 apps), ISC (1 apps).

How much does it cost to self-host Communication - Email - Mail Transfer Agents software?

The software itself is free to download. Based on our rough hardware estimates, the cheapest suitable VPS plan starts at about $3.5/month (median $3.5/month across apps in this category). Several light apps can share one server.

Figures from GitHub and Docker Hub as of 2026-11-15; hosting costs are rough estimates.