The hold action now holds (dlp-and-mail-flow-rules spec, §2.6), where until now it blocked. - At DATA a hold decision queues the message with its release a century off (the queue's future-release mechanism, so the stored format is unchanged and an older node just never sends it), transport rules still applied, and replies 250 Held for review. A review record under R/h + queue id keeps the sender, recipients, subject, size, rules and detector counts. The sender is told when the rule asks. - smtp/queue/held.rs: release (each recipient due now, its next notice as far off as it was, its lifetime counted from the release), reject (removed from the queue, the sender told, with the reviewer's note), and expiry: the daily clean-up rejects what nobody reviewed in 7 days, recorded as the server's doing. - inbuxa:HeldMessage get/set: the review queue, sysDlpReviewGet to list and read (preview, 64 KB of text, only when asked for and recorded as blobAccess), sysDlpReviewUpdate to release or reject, a reason required and audited by the request layer; no create or destroy; server-level only. - Guards: Emails > Queue refuses to change or delete held mail; the sender can't unsend it. - Privacy catalog entry for inbuxa:HeldMessage; spec §2.6 as built. Tests: mail_rules_tests gains the whole flow (held and listed with counts, sender notified and nothing delivered, queue and unsend refused, preview recorded, reject needs a reason and tells the sender the note, release delivers, expiry returns it, decisions audited with reasons). smtp inbound, system_tests (after one BlobNotFound in antispam, the known flake, then clean), features and common unit tests.
A complete mail and collaboration server, every feature included, under the AGPL
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, anddocs/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 aren't read: the server stops at startup and
names each one to rename.
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.