Best Haraka Alternatives & Competitors in 2025

An open source mailserver suite.

Key mailcow features:

Comprehensive Feature Set Open Source Docker-based Deployment Active Community and Support

Open Source

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

Key Postfix features:

Security Performance Compatibility Reliability

The #1 email warming service to improve your deliverability by generating realistic and meaningful engagement to your emails. Easy-to-use solution to help you land in the main inbox instead of the spam folder. .

Key MailReach.co features:

Deliverability Improving Email Warming Meaningful Warming Content Smart Warming Algorithm

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Mail-in-a-Box provides webmail and an IMAP/SMTP server for use with mobile devices and desktop mail software and also includes contacts and calendar synchronization.

Key Mail-in-a-box features:

Ease of Setup Full Control Cost-effective Open Source

Open Source

Mailu is a simple yet full-featured mail server as a set of Docker images.

Key Mailu features:

Open Source Lightweight Modularity Docker-based Deployment

Self hosted modern mail server.

Key WildDuck features:

Open Source Modern Protocol Support Scalability Multi-domain Support

Open Source

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.

Key Zimbra features:

Open Source Cost-Effective Scalability Feature-Rich

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

Key iRedMail features:

Open Source Comprehensive Features Easy Installation Excellent Documentation

Open Source

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

Key PowerMTA features:

High Deliverability Scalability Advanced Analytics Customization

Modoboa is a mail hosting and management platform including a modern and simplified Web User Interface.

Key Modoboa features:

Open Source Integration User-Friendly Interface Mail Security

Full featured email server built in docker with free plan.

Key Poste.io features:

User-Friendly Interface Comprehensive Features Quick Setup Open Source

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

Key MailerQ features:

High Performance Flexible Configuration Scalability Real-time Monitoring

Web-based IMAP email client.

Key Roundcube features:

Open Source User-Friendly Interface Extensibility Security

Open Source

OpenSMTPD is a FREE implementation of the server-side SMTP protocol as defined by RFC 5321, with...

Key OpenSMTPD features:

Simplicity Security-focused Lightweight Integration with OpenBSD

Open Source