There are 7 open-source alternatives to Mailcow in this directory. The most popular is Docker-mailserver with 18.1k GitHub stars, followed by Mailinabox(15.3k stars). All are open source, free to use, and many can be self-hosted.
| # | Tool | Stars | Language | License |
|---|---|---|---|---|
| 1 | Docker-mailserver 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. | 18.1k | Shell | MIT License |
| 2 | Mailinabox 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. | 15.3k | Python | Creative Commons Zero v1.0 Universal |
| 3 | BillionMail 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. | 12.4k | Go | GNU Affero General Public License v3.0 |
| 4 | Stalwart 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. | 12.3k | Rust | — |
| 5 | BillionMail BillionMail provides an open-source MailServer solution with NewsLetter and Email Marketing capabilities—fully self-hosted, developer-friendly, and free from monthly fees. | 8.3k | Go | GNU Affero General Public License v3.0 |
| 6 | Mailu 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. | 7.0k | Python | Other |
| 7 | Modoboa 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. | 3.5k | Python | ISC License |
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 three are Docker-mailserver(18.1k stars), Mailinabox(15.3k stars), BillionMail(12.4k stars). All are open source and free to use.
Yes. Every tool listed here is open source and free to use in your own projects. Many can be self-hosted on your own infrastructure, which means no subscription fees and full control over your data.
Many of the alternatives listed are self-hostable. Each tool's page lists hosting details, system requirements, and licensing terms.
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