Best Halon MTA Alternatives & Competitors in 2025

KumoMTA is the world's first Open-Source MTA designed from the ground-up for large-volume senders. Get a fast, flexible, supported solution.

Open Source free

MailerQ is a high performance Mail Transfer Agent (MTA) designed for delivering large volume email messages at very high speeds.

Seamless project management and collaboration for your team.

Visit website $12.0 / Monthly (Per user)

PowerMTA is an industrial-strength software for high-volume email delivery.

Postfix is a mail transfer agent (MTA) that routes and delivers electronic mail.

GreenArrow Transactional Email provides a flexible and secure SMTP and API email delivery from application or website.

Zimbra is trusted by over 500 million users to increase productivity with a complete set of collaboration tools while maintaining total control over security and privacy.

Exim is a message transfer agent (MTA) developed at the University of Cambridge for use on Unix systems connected to the Internet.

Open Source

An open source mailserver suite.

Open Source

NikaMail is a portable, extendable, zero-config email server.

Scale your business email & marketing messages with Amazon Simple Email Service (SES), a cost-effective and reliable cloud email service. Sign up today.

Open Source

Sendmail is a general purpose internetwork email routing facility that supports many kinds of...

A set of powerful APIs that enable you to send, receive and track email from your app effortlessly whether you use Python, Ruby, PHP, C#, Node.js or Java.

Open Source

A fully fledged, free email server solution, an open source project (GPL v2).

Open Source