A node that started while NATS was down never got a coordinator. The
connect failed at boot, bootstrap recorded a build error and the node ran
with Coordinator::None until restarted. It had no broadcast subscriber
or publisher, so cross-node push and cache invalidation to it stayed
broken, and its healthcheck said nothing about it. Losing NATS after
startup was silent too.
- The NATS client now connects in the background
(retry_on_initial_connect): startup never waits on NATS or fails over
it, the node gets its coordinator, subscriber and publisher at once,
and the client keeps trying (async-nats's backoff, at most 4 s apart)
until NATS answers. Subscriptions made meanwhile start delivering when
it does. A configured maxReconnects still ends the attempts.
- Three new events report the connection: cluster.coordinator-connected
(info), cluster.coordinator-disconnected (warn: lost, closed, gave up,
or not connected within the connection timeout at startup) and
cluster.coordinator-error (warn: a failed attempt, reported once per
outage rather than every retry, and server errors, slow consumers and
lame duck mode). They are in the packaged schema, ids 644 to 646.
- GET /healthz/cluster reports the coordinator: 200
{"coordinator":"connected"}, 503 {"coordinator":"disconnected"}, or
200 with "none" (no coordinator) or "unknown" (a backend that doesn't
track its connection). /healthz/live and /healthz/ready are unchanged
on purpose: a node without its coordinator still serves mail, and
failing those would have orchestrators restart, or pull out of
service, every node at once whenever NATS is down.
Only NATS connects lazily; the other coordinator backends still fail at
boot as before.
cluster::coordinator::coordinator_reconnect_tests starts a node against a
NATS port with nothing behind it, checks it boots with a coordinator and
reports it disconnected, subscribes, then starts NATS on that port: the
node connects on its own and the subscription receives a message from a
second client. Stopping and restarting NATS shows disconnected, then
connected, and the same subscription keeps working.
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.