Maddy
A one-binary mail server learning to behave like production infrastructure.
Comparison · Comms
mailcow vs Synapse
A side-by-side editorial comparison of mailcow and Synapse — release velocity, themes, recent moves, and the top alternatives to consider.
mailcow vs Synapse: 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 Synapse?
The reference Matrix homeserver shipping protocol work on a tight release train
Synapse is moving through the 1.156–1.158 line at roughly weekly cadence, with release candidates preceding each stable. The functional work is protocol-level: MSC4140 cancellable delayed events with per-user scheduling limits, MSC4354 sticky events exposed over MSC4186 simplified sliding sync, and stabilized ephemeral event sending. Version 1.157.0rc1 removed the deprecated MSC3861 auth delegation, and 1.157.2 was an out-of-band security release addressing several vulnerabilities rated up to high severity.
mailcow vs Synapse: 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.
Synapse
5.0COMMS
The reference Matrix homeserver shipping protocol work on a tight release train
◆ Current state
Synapse is moving through the 1.156–1.158 line at roughly weekly cadence, with release candidates preceding each stable. The functional work is protocol-level: MSC4140 cancellable delayed events with per-user scheduling limits, MSC4354 sticky events exposed over MSC4186 simplified sliding sync, and stabilized ephemeral event sending. Version 1.157.0rc1 removed the deprecated MSC3861 auth delegation, and 1.157.2 was an out-of-band security release addressing several vulnerabilities rated up to high severity.
◆ Where it's heading
Development tracks the Matrix spec process directly — features arrive as MSCs graduate, and deprecated experimental paths are removed once replacements stabilize. Sliding sync is the load-bearing effort, with sticky events and ephemeral sending both being routed through it. The security release and the config regression that followed 1.157.0 show the cost of that cadence: fast lines need fast patches.
◆ Prediction
Expect the 1.158 line to continue folding MSCs into sliding sync, and further removal of experimental_features flags whose MSCs have stabilized, following the MSC3861 precedent.
Alternatives to mailcow and Synapse
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 Synapse.
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 Synapse alternatives →
Recent activity from mailcow and Synapse
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 1d agoSynapse1.158 release candidate opens
- 2d agomailcow🏖️🐮 Mooly 2026 | Postfix 3.10.12, Rspamd 4.1.0 & Nginx 1.30.3 - Revision A
- 4d agoSynapseOut-of-band security release for federated homeservers
- 9d agoSynapseConfig regression on falsy experimental_features fixed
- 10d agoSynapseCancellable delayed events reach stable
- 16d agoSynapseMSC3861 auth delegation removed in 1.157 RC
- 19d agomailcow🏖️🐮 Mooly 2026 | Postfix 3.10.12, Rspamd 4.1.0 & Nginx 1.30.3
- 25d agoSynapseSticky events exposed over simplified sliding sync
- 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 Synapse?
They serve adjacent needs but don't currently overlap on shipped themes. mailcow and Synapse 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 Synapse?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. mailcow and Synapse 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 Synapse?
Top Synapse alternatives in Comms are ranked by recent ship velocity. Browse the "Synapse alternatives" section above for the current picks, or visit /alternatives/synapse for the full list with editorial commentary on each.