Maddy
A one-binary mail server learning to behave like production infrastructure.
Comparison · Comms
mailcow vs Mailu
A side-by-side editorial comparison of mailcow and Mailu — release velocity, themes, recent moves, and the top alternatives to consider.
mailcow vs Mailu: at a glance
What is mailcow?
Six releases, and every one of them is a security update in some form.
mailcow ships on a monthly tag with lettered revisions, and this window contains no release that isn't security-driven. The May line ran to three revisions in two weeks — an unnamed fix with a CVE identifier withheld until later, SOGo 5.12.8 covering four upstream issues, an unbound CVE, HTML escaping added to the quarantine table, sieve filter editor and queue manager. July brought Rspamd 4.1.0 and later 4.1.4, nginx 1.30.3 and a CVE fix, Postfix moved off bookworm, and a release described only as hardening.
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.
mailcow vs Mailu: editorial side-by-side
mailcow
5.0COMMS
Six releases, and every one of them is a security update in some form.
◆ Current state
mailcow ships on a monthly tag with lettered revisions, and this window contains no release that isn't security-driven. The May line ran to three revisions in two weeks — an unnamed fix with a CVE identifier withheld until later, SOGo 5.12.8 covering four upstream issues, an unbound CVE, HTML escaping added to the quarantine table, sieve filter editor and queue manager. July brought Rspamd 4.1.0 and later 4.1.4, nginx 1.30.3 and a CVE fix, Postfix moved off bookworm, and a release described only as hardening.
◆ Where it's heading
Two distinct pressures are visible. One is upstream: mailcow bundles Postfix, Rspamd, SOGo, nginx, unbound and Dovecot, so every one of their advisories becomes a mailcow release, and the base image migration from bookworm to trixie is that same maintenance surfacing at the OS layer. The other is the project's own web UI, where output escaping is being retrofitted view by view — quarantine table, sieve editor, queue manager, quarantine overview — which reads as a systematic pass rather than isolated reports. Earlier releases in the feed show where feature work went when it happened: forced 2FA, ACME DNS-01 challenges, and admin controls over EAS and DAV access.
◆ Prediction
Expect the monthly-plus-revisions rhythm to continue with upstream component bumps driving most of it, and the web UI escaping pass to reach the remaining admin views.
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.
Alternatives to mailcow and Mailu
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 mailcow or Mailu.
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.
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.
Notion
Notion is turning Custom Agents into event-driven workers with their own runtime and billing.
See all mailcow alternatives → · See all Mailu alternatives →
Recent activity from mailcow and Mailu
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 2d agomailcow🏖️🐮 Mooly 2026 | Postfix 3.10.12, Rspamd 4.1.0 & Nginx 1.30.3 - Revision A
- 6d agoMailuAutoconfig fix for modern K-9 Mail
- 8d agoMailuRoundcube 1.6.17 closes two CVEs
- 13d agoMailuSets X-Forwarded-By in response to a GHSA advisory
- 19d agomailcow🏖️🐮 Mooly 2026 | Postfix 3.10.12, Rspamd 4.1.0 & Nginx 1.30.3
- 27d agoMailuAdmin UI keeps form values on failed submit
- 1mo agoMailuEscapes sieve fields, fixing autoreplies with special characters
- 2mo agoMailuRoundcube 1.6.16 and carddav 5.1.3 close CVE-2026-49217
- 2mo agomailcowThird May revision: unbound CVE and nginx 1.30.2
- 2mo agomailcowSecond May revision: quarantine table HTML escaping
- 2mo agomailcowSOGo 5.12.8 covering four upstream security issues
- 2mo agomailcowMay base release: undisclosed CVE plus web UI escaping
Frequently asked questions
What is the difference between mailcow and Mailu?
They serve adjacent needs but don't currently overlap on shipped themes. mailcow and Mailu 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 mailcow better than Mailu?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. mailcow and Mailu 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 mailcow?
Top mailcow alternatives in Comms are ranked by recent ship velocity. Browse the "mailcow alternatives" section above for the current picks, or visit /alternatives/mailcow for the full list with editorial commentary on each.
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.