Looking for an open-source alternative to Mailcow? Below are 7 community-built tools that offer similar functionality — all free, open source, and ready to use or self-host. Ranked by GitHub stars.
A production-ready, fullstack mail server solution featuring SMTP, IMAP, LDAP, Antispam, and Antivirus functionalities, all running seamlessly inside a container. Designed for simplicity and ease of setup with robust security and reliability.
Mail-in-a-Box helps individuals take back control of their email by defining a one-click, easy-to-deploy SMTP+everything else server: a mail server in a box.
BillionMail is an open-source, fully self-hosted mail server solution with integrated newsletter and email marketing capabilities. It is designed for developers and businesses seeking powerful, flexible, and cost-effective alternatives to proprietary mailing platforms without any recurring fees.
Stalwart is an all-in-one mail and collaboration server designed to be secure, scalable, and highly compatible with a wide range of protocols including IMAP, JMAP, SMTP, CalDAV, CardDAV, and WebDAV. It provides enterprise-class communication and groupware functionality in a single unified solution.
BillionMail provides an open-source MailServer solution with NewsLetter and Email Marketing capabilities—fully self-hosted, developer-friendly, and free from monthly fees.
Mailu is a full-featured, self-hosted email server solution that runs as Docker images, providing an insular email distribution with modern features and security controls.
Modoboa is an open-source platform that simplifies mail hosting by providing a modern and user-friendly web interface for managing email domains, mailboxes, and aliases. It features integrated administration, security enhancements, and extensibility for hassle-free email server management.
The top picks from this list are Docker-mailserver, Mailinabox, BillionMail — all maintained, free to use, and self-hostable.
Yes. Every tool listed here is open source and free to use. Many can be self-hosted on your own infrastructure, which means no subscription fees and full control over your data.
Most of the alternatives listed are self-hostable. Check each tool's page for hosting details, system requirements, and licensing terms.
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