A school, or any organization that doesn't want people's mailboxes shared, can now turn that off (multi-account spec, MA-C). Two switches at two levels, as the legacy-protocols switch has: - mailSharing: people may share their own mail folders; - addAccounts: people may add other accounts to the webmail (read by the webmail's account switcher, MA-B). inbuxa:SharingPolicy/get and /set hold them: the server's policy has the singleton id, each tenant's has the tenant's id. Both default to on, so nothing changes until someone turns one off. A tenant's administrator changes their own tenant's (the domain's permissions, as for its protocols switch); only a server administrator with sysSharingUpdate changes the server's; a tenant can never be looser than the server (forbidden). Every change goes through the audit log, and rebuilds every access token, here and on every node. With mail sharing off for an account's tenant (or the server): - Mailbox/set and IMAP SETACL refuse to start or widen a share (forbidden / NO [NOPERM]); narrowing or ending one is always allowed; - shares already made give nothing while it is off: an access token leaves out mailbox grants from such an owner. They stay stored, so turning sharing back on restores them (John, 2026-10-05); - a lock's and a shared mailbox's grants are an administrator's and always count, and group membership was never a share. The session's own account says mailSharing and addAccounts, the stricter of the two levels, so front ends can hide what is off. Tests: a new sharing_policy suite with a school tenant, its own administrator and two people outside it: on by default; the school's administrator turns it off but can't touch the server's; an old share stops working and a new one is refused while someone outside the school is unaffected; a shared mailbox in the school keeps working; the server off can't be loosened by the tenant; on again restores the old share; ending a share works while off; and every change is audited. A unit test covers the stricter-only rule. sharing_policy_tests, jmap_tests, imap_tests, account_lock_tests and audit_log_tests pass (RocksDB).
A complete mail and collaboration server, every feature included, under the AGPL
Note
Development happens on git.coffeylabs.org/inbuxa/inbuxa-server; the copy on GitHub is a read-only mirror. Report issues at git.coffeylabs.org/inbuxa/inbuxa-server/issues, and join discussions at community.coffeylabs.org.
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.