Looking for an open-source alternative to Zimbra? Below are 2 community-built tools that offer similar functionality — all free, open source, and ready to use or self-host. Ranked by GitHub stars.
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.
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 Stalwart, Modoboa — 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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