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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.

Shared themes:self-hosted

mailcow vs Synapse: at a glance

FeaturemailcowSynapse
SectorCommsComms
Velocity score5.05.0
Sparks · 30d00
Top themesmail-server, self-hosted, security-updates, dockermatrix-protocol, homeserver, security-patches, spec-compliance
Last editorial update1h ago3h ago
WebsiteVisit →Visit →

What is mailcow?

mailcow's monthly releases are mostly upstream security updates with small UI work

mailcow ships named monthly releases with lettered revisions, and most exist to pull in upstream security fixes for components like SOGo, Nginx, Redis, Unbound and Rspamd. The September release also added an ACL and global switch to stop external alias forwarding, a show-password toggle on login pages, and fixes such as an auth-cache wipe during nginx outages. October moved PHP to an Alpine 3.24 base and brought SOGo 5.12.12, Nginx 1.30.6 and a UI update.

Read the full mailcow trajectory →

What is Synapse?

Synapse 1.164 advertises Matrix v1.16 and v1.17 amid a run of dependency security patches

Synapse keeps its two-to-three-week cycle of candidates and stables. 1.164.0 went stable on 27 October with support for Matrix v1.16 and v1.17 and a dedicated endpoint for scheduling delayed events (MSC4140). The surrounding releases are security dependency bumps: certifi, a rustls-webpki update that distrusts the compromised eMudhra intermediate CAs, Pillow 13.0.0 for critical image-handling flaws, and msgpack against memory exhaustion on the public room list.

Read the full Synapse trajectory →

mailcow vs Synapse: editorial side-by-side

M
mailcow
COMMS
5.0

mailcow's monthly releases are mostly upstream security updates with small UI work

◆ Current state

mailcow ships named monthly releases with lettered revisions, and most exist to pull in upstream security fixes for components like SOGo, Nginx, Redis, Unbound and Rspamd. The September release also added an ACL and global switch to stop external alias forwarding, a show-password toggle on login pages, and fixes such as an auth-cache wipe during nginx outages. October moved PHP to an Alpine 3.24 base and brought SOGo 5.12.12, Nginx 1.30.6 and a UI update.

◆ Where it's heading

Keeping a dozen bundled upstreams current is the product, and the cadence is built around that. Feature work arrives in small admin and web UI controls alongside the security updates.

◆ Prediction

Expect a revision of the October release carrying further upstream updates, following the lettered-revision pattern.

S
Synapse
COMMS
5.0

Synapse 1.164 advertises Matrix v1.16 and v1.17 amid a run of dependency security patches

◆ Current state

Synapse keeps its two-to-three-week cycle of candidates and stables. 1.164.0 went stable on 27 October with support for Matrix v1.16 and v1.17 and a dedicated endpoint for scheduling delayed events (MSC4140). The surrounding releases are security dependency bumps: certifi, a rustls-webpki update that distrusts the compromised eMudhra intermediate CAs, Pillow 13.0.0 for critical image-handling flaws, and msgpack against memory exhaustion on the public room list.

◆ Where it's heading

The homeserver tracks the spec closely, stabilising MSCs as they land in Matrix releases, while backporting each security bump to the previous stable line. Sticky Events and User Status work suggest continued alignment with newer client features.

◆ Prediction

1.165 release candidates should follow within about two weeks, likely with further MSC stabilisations.

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. 4d agoSynapseSynapse 1.164.1: msgpack memory-exhaustion fix, status clearing
  2. 6d agoSynapseSynapse 1.164.0: Matrix v1.16/v1.17 support goes stable
  3. 9d agoSynapseSynapse 1.164.0rc3: Pillow 13 security bump
  4. 9d agoSynapseSynapse 1.163.2: Pillow critical security backport
  5. 10d agoSynapseSynapse 1.164.0rc2: certificate trust updates
  6. 10d agoSynapseSynapse 1.163.1: eMudhra CA distrust and certifi update
  7. 11d agomailcow🎃🐮 Mooctober 2026 | Security Update: PHP 8.2.35, SOGo 5.12.12 & Nginx 1.30.6
  8. 27d agomailcow2026-09a: Rspamd 4.2.1 and postfix-tlspol bumps
  9. 1mo agomailcow🍂🐮 Mootember 2026 | Unbound 1.26.1, SOGo 5.12.11 & Redis 7.4.11
  10. 2mo agomailcow🏖️🐮 Mooly 2026 | Postfix 3.10.12, Rspamd 4.1.0 & Nginx 1.30.3 - Revision B
  11. 3mo agomailcow🏖️🐮 Mooly 2026 | Postfix 3.10.12, Rspamd 4.1.0 & Nginx 1.30.3 - Revision A
  12. 3mo agomailcow🏖️🐮 Mooly 2026 | Postfix 3.10.12, Rspamd 4.1.0 & Nginx 1.30.3

Frequently asked questions

What is the difference between mailcow and Synapse?

Both compete on the same themes — self-hosted — within Comms. 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.