A complete mail and collaboration server, every feature included, under the AGPL

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INBUXA is a mail and collaboration server: JMAP, IMAP, POP3, SMTP, CalDAV, CardDAV and WebDAV, in one Rust binary, with ihasmail as its web front end. It is a fork of Stalwart. Project site: inbuxa.org. Documentation: docs.inbuxa.org.

Stalwart ships some features only in a paid Enterprise Edition: multi-tenancy, masked email, undelete and others. INBUXA ships everything to everybody under the AGPL-3.0, rebuilding those features independently and without using any of Stalwart's Enterprise code.

What's different from Stalwart

• Every feature, one edition. No license key, no edition checks, no upsell. See docs/spec/SPEC.md §4 for the features being rebuilt, and docs/spec/features/ for each one's specification.
• Webmail and administration by ihasmail, as a separate service that can run beside the server or elsewhere. Stalwart's own web interface is removed, so there's no web front end on the mail host.
• Clean-room rebuilds. Enterprise-only code is stripped from every upstream release before it's imported. The rebuilt features are written from specifications that use only public sources (docs/spec/SPEC.md §3).

How the fork is kept

Upstream releases arrive as stripped snapshots, never with upstream's git history, which contains Enterprise code. tools/fork/strip.py builds each snapshot on top of upstream's own ossify.py, then verifies it independently. The report for every import is in docs/fork/strip-reports/. See docs/spec/SPEC.md §2.

Building

cargo build --release -p inbuxa          # the binary is target/release/inbuxa
docker build -t inbuxa .                 # or the container image

Settings are read from INBUXA_* environment variables. An existing Stalwart install's STALWART_* variables still work, with a warning to rename them. New installs keep their data in /var/lib/inbuxa and logs in /var/log/inbuxa. Existing installs keep the paths their configuration already names, so none of their data moves.

License and credits

INBUXA is free software under the GNU Affero General Public License, version 3.

It is a fork of Stalwart, copyright © Stalwart Labs LLC, modified by Coffey Labs in 2026. Upstream's copyright notices are kept on every file they cover, and every upstream file this fork changed says so in its header, under the notice it came with. Stalwart's files are dual-licensed AGPL-3.0-only or Stalwart's Enterprise License, and INBUXA takes them under the AGPL-3.0 only. A few of those files also carry code from other projects under MIT or BSD licenses, which stays under those licenses; THIRD-PARTY.md lists it with its notices. "Stalwart" is Stalwart Labs' name. INBUXA isn't affiliated with or endorsed by Stalwart Labs.

The INBUXA mark reuses ihasmail's cat-and-envelope artwork.