Maddy
A one-binary mail server learning to behave like production infrastructure.
Comparison · Comms
Mailu vs Stalwart
A side-by-side editorial comparison of Mailu and Stalwart — release velocity, themes, recent moves, and the top alternatives to consider.
Mailu vs Stalwart: at a glance
What is Mailu?
A mail server whose entire visible output is patching other people's code.
Mailu is a self-hosted mail suite shipped as a Docker compose stack, and the 2024.06.x branch shown here is its maintenance line. Every release in the window is a single-issue patch — a Roundcube bump, a CVE fix, an autoconfig tweak. The cadence looks high at ten pinned releases in five months, but each carries one change.
What is Stalwart?
Stalwart keeps chasing standards nobody has implemented yet — DKIM2, DMARCbis, now JMAP email push.
Stalwart is a single-binary mail and collaboration server covering JMAP, IMAP, SMTP, CalDAV and CardDAV. The 0.16.x line ships roughly weekly and its additions cluster in one place: implementing IETF drafts and fresh RFCs ahead of the field, while a long tail of JMAP conformance and MTA edge-case fixes runs underneath. The latest release adds JMAP email delivery push notifications, completing a push stack built across the last three releases.
Mailu vs Stalwart: editorial side-by-side
Mailu
5.0COMMS
A mail server whose entire visible output is patching other people's code.
◆ Current state
Mailu is a self-hosted mail suite shipped as a Docker compose stack, and the 2024.06.x branch shown here is its maintenance line. Every release in the window is a single-issue patch — a Roundcube bump, a CVE fix, an autoconfig tweak. The cadence looks high at ten pinned releases in five months, but each carries one change.
◆ Where it's heading
Most of what Mailu ships is downstream maintenance of its bundled components, Roundcube above all, which drove three of these ten releases. The project's own work here is defensive: escaping user-controlled fields in generated sieve scripts, setting X-Forwarded-By, adapting to Microsoft's new autodiscover. This is a product in steady-state operation, where the release notes track what upstream broke rather than what Mailu decided to build.
◆ Prediction
The next pinned release will most likely be another Roundcube or Alpine bump, since component upgrades triggered half the releases here. These entries say nothing about what is happening on the main branch.
Stalwart
5.0COMMS
Stalwart keeps chasing standards nobody has implemented yet — DKIM2, DMARCbis, now JMAP email push.
◆ Current state
Stalwart is a single-binary mail and collaboration server covering JMAP, IMAP, SMTP, CalDAV and CardDAV. The 0.16.x line ships roughly weekly and its additions cluster in one place: implementing IETF drafts and fresh RFCs ahead of the field, while a long tail of JMAP conformance and MTA edge-case fixes runs underneath. The latest release adds JMAP email delivery push notifications, completing a push stack built across the last three releases.
◆ Where it's heading
The push story is the clearest arc: Web Push payload and subscription fixes in 0.16.10, VAPID per RFC 9749 in 0.16.14, and the emailpush draft in 0.16.16. Parallel to it, 0.16.12 landed DKIM2 and the DMARCbis trio, and the fix lists keep narrowing toward strict-spec behaviour — DMARC alignment reporting, SMTP line-length limits, BDAT error codes. Stalwart is positioning as the reference implementation of modern mail standards rather than competing on features.
◆ Prediction
Expect the JMAP push work to keep filling in — subscription lifecycle, delivery semantics — alongside continued DKIM2 and DMARCbis refinement as those drafts move. The fix cadence suggests operational hardening around clustering and Redis locking is the other near-term thread.
Alternatives to Mailu and Stalwart
Other Comms products tracked by Sparkpulse, ranked by recent ship velocity. Each card links to a full editorial trajectory and lets you pivot into a head-to-head comparison with either Mailu or Stalwart.
Friendica
Friendica keeps betting on being the fediverse node that speaks everyone else's protocols.
diaspora
The original federated social network now ships roughly once every two years.
mailcow
Six releases, and every one of them is a security update in some form.
Element iOS
Renamed Element Classic, this client now ships one small fix every few months
Twilio
Twilio is selling trust: branded calls, scoped keys, and stricter sender vetting.
See all Mailu alternatives → · See all Stalwart alternatives →
Recent activity from Mailu and Stalwart
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 16h agoStalwartv0.16.16 — JMAP email push, plus Redis lock and SMTP relay fixes
- 7d agoStalwartv0.16.15 — JMAP, MTA, and auth privilege fixes
- 7d agoMailuAutoconfig fix for modern K-9 Mail
- 9d agoMailuRoundcube 1.6.17 closes two CVEs
- 13d agoStalwartv0.16.14 — VAPID Web Push plus push and calendar fixes
- 15d agoMailuSets X-Forwarded-By in response to a GHSA advisory
- 21d agoStalwartv0.16.13 — FreeBSD support and OAuth/JMAP fixes
- 27d agoStalwartv0.16.12 — DKIM2 and DMARCbis email-authentication support
- 28d agoMailuAdmin UI keeps form values on failed submit
- 1mo agoMailuEscapes sieve fields, fixing autoreplies with special characters
- 1mo agoStalwartv0.16.11 — S/MIME encryption-at-rest and Redis Sentinel backend
- 2mo agoMailuRoundcube 1.6.16 and carddav 5.1.3 close CVE-2026-49217
Frequently asked questions
What is the difference between Mailu and Stalwart?
They serve adjacent needs but don't currently overlap on shipped themes. Mailu and Stalwart are shipping at a similar cadence (velocity 5.0 vs 5.0, both within Sparkpulse's "active" band). See the at-a-glance table above for a side-by-side breakdown of velocity, recent sparks, and editorial themes.
Is Mailu better than Stalwart?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. Mailu and Stalwart are shipping at a similar cadence (velocity 5.0 vs 5.0, both within Sparkpulse's "active" band). For your specific use case, the alternatives sections above list other Comms products to evaluate alongside.
What are the best alternatives to Mailu?
Top Mailu alternatives in Comms are ranked by recent ship velocity. Browse the "Mailu alternatives" section above for the current picks, or visit /alternatives/mailu for the full list with editorial commentary on each.
What are the best alternatives to Stalwart?
Top Stalwart alternatives in Comms are ranked by recent ship velocity. Browse the "Stalwart alternatives" section above for the current picks, or visit /alternatives/stalwart for the full list with editorial commentary on each.