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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

FeaturemailcowSynapse
SectorCommsComms
Velocity score5.05.0
Sparks · 30d00
Top themesmail-server, self-hosted, security-updates, dockermatrix-protocol, federation, homeserver, security-releases
Last editorial update1d ago7d ago
WebsiteVisit →Visit →

What is mailcow?

mailcow's release notes are almost entirely upstream security currency.

mailcow ships named seasonal releases with lettered revisions, and nearly every revision exists to pull in an upstream security fix - Redis, ClamAV, SOGo, Rspamd, nginx, unbound, Postfix. Revision B of the Mooly 2026 release updates Redis 7.4.10, ClamAV 1.4.6, and SOGo 5.12.10, adds minor web UI and nginx hardening, and removes a legacy DeltaChat sieve rule. The last release with genuinely new features was the March cut, which added forced 2FA, ACME DNS-01 challenges, and a passwordless autodiscover endpoint.

Read the full mailcow trajectory →

What is Synapse?

Synapse alternates release candidates with security patches on a tight two-week cycle

The feed is a straight release stream on a roughly two-week rhythm: a release candidate, a final, then point releases as needed. Recent substance sits in 1.157.0 — limits on scheduled delayed events, backward movement of fully read markers, time filters on the user-redaction admin API, and a configuration option to stop presence routing between users who merely share a room. 1.157.2 followed as a security release covering eleven advisories, six of them high severity.

Read the full Synapse trajectory →

mailcow vs Synapse: editorial side-by-side

M
mailcow
COMMS
5.0

mailcow's release notes are almost entirely upstream security currency.

◆ Current state

mailcow ships named seasonal releases with lettered revisions, and nearly every revision exists to pull in an upstream security fix - Redis, ClamAV, SOGo, Rspamd, nginx, unbound, Postfix. Revision B of the Mooly 2026 release updates Redis 7.4.10, ClamAV 1.4.6, and SOGo 5.12.10, adds minor web UI and nginx hardening, and removes a legacy DeltaChat sieve rule. The last release with genuinely new features was the March cut, which added forced 2FA, ACME DNS-01 challenges, and a passwordless autodiscover endpoint.

◆ Where it's heading

For a self-hosted mail stack that bundles a dozen upstream components, keeping current with their CVEs is the product, and mailcow has organized its release cadence around exactly that. The pattern is consistent: a named release with some feature content every few months, then lettered revisions that are pure security currency plus small web UI escaping and validation fixes. The web interface is where mailcow's own code gets hardened - HTML escaping in quarantine views and sieve editors recurs across several revisions.

◆ Prediction

Expect the next entry to be another lettered revision carrying upstream updates, with the next named release likely bundling whatever feature work has accumulated since March.

S
Synapse
COMMS
5.0

Synapse alternates release candidates with security patches on a tight two-week cycle

◆ Current state

The feed is a straight release stream on a roughly two-week rhythm: a release candidate, a final, then point releases as needed. Recent substance sits in 1.157.0 — limits on scheduled delayed events, backward movement of fully read markers, time filters on the user-redaction admin API, and a configuration option to stop presence routing between users who merely share a room. 1.157.2 followed as a security release covering eleven advisories, six of them high severity.

◆ Where it's heading

Development is tracking the Matrix specification process rather than a product roadmap of its own — most features arrive as implementations of numbered MSCs, several contributed from outside. The operational theme underneath is load and blast radius: presence exclusion, caps on delayed events, and locked sliding-sync connections all reduce what a busy homeserver has to carry. Security handling is centralized and batched, shipped as one patch release rather than trickled out.

◆ Prediction

Expect 1.159.0 to follow its release candidate within roughly a week, continuing the MSC-implementation pattern. The recent removal of deprecated auth delegation suggests more cleanup of experimental configuration in the coming releases.

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.

See all mailcow alternatives → · See all Synapse alternatives →

Recent activity from mailcow and Synapse

Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.

  1. 1d agomailcow🏖️🐮 Mooly 2026 | Postfix 3.10.12, Rspamd 4.1.0 & Nginx 1.30.3 - Revision B
  2. 7d agoSynapsev1.159.0rc1
  3. 14d agoSynapsev1.158.0
  4. 19d agoSynapsev1.158.0rc1
  5. 20d agomailcow🏖️🐮 Mooly 2026 | Postfix 3.10.12, Rspamd 4.1.0 & Nginx 1.30.3 - Revision A
  6. 21d agoSynapseSynapse 1.157.2 patches 11 security advisories, six high severity
  7. 27d agoSynapseSynapse 1.157.1 fixes falsy experimental_features config regression
  8. 28d agoSynapseSynapse 1.157.0 adds delayed-event limits and QR sign-in support
  9. 1mo agomailcow🏖️🐮 Mooly 2026 | Postfix 3.10.12, Rspamd 4.1.0 & Nginx 1.30.3
  10. 2mo agomailcowThird May revision: unbound CVE and nginx 1.30.2
  11. 3mo agomailcowSecond May revision: quarantine table HTML escaping
  12. 3mo agomailcowSOGo 5.12.8 covering four upstream security issues

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.