Postmark
Postmark adds its own SOC 2 Type 2 report to a run of security work.
Comparison · Comms
mailcow vs Proton Bridge
A side-by-side editorial comparison of mailcow and Proton Bridge — release velocity, themes, recent moves, and the top alternatives to consider.
mailcow vs Proton Bridge: at a glance
What is mailcow?
mailcow's November release patches an admin RCE and reworks sync jobs.
mailcow ships named monthly releases with lettered revisions, mostly to pull in upstream security fixes for SOGo, Nginx, Redis, Unbound and Rspamd. The November release goes further: it fixes a remote code execution flaw reachable by admins and domain admins, adds mailbox groups, and reworks imapsync so sync jobs reference a separate source. It also caps request bodies at 64 MB, which breaks large SOGo and ActiveSync mail unless NGINX_MAX_BODY_SIZE is raised.
What is Proton Bridge?
Proton Bridge v3.27.2 adds support for the oo7 keyring on Linux.
Proton Bridge's releases in 2026 have been almost entirely maintenance: monthly vulnerability patches, Go toolchain bumps, IMAP RFC-compliance fixes and recovery from corrupted sync state files. v3.27.2 adds one item, support for the oo7 keyring service, a Rust-based Secret Service implementation used on newer Linux desktops.
mailcow vs Proton Bridge: editorial side-by-side
mailcow
5.0COMMS
mailcow's November release patches an admin RCE and reworks sync jobs.
◆ Current state
mailcow ships named monthly releases with lettered revisions, mostly to pull in upstream security fixes for SOGo, Nginx, Redis, Unbound and Rspamd. The November release goes further: it fixes a remote code execution flaw reachable by admins and domain admins, adds mailbox groups, and reworks imapsync so sync jobs reference a separate source. It also caps request bodies at 64 MB, which breaks large SOGo and ActiveSync mail unless NGINX_MAX_BODY_SIZE is raised.
◆ Where it's heading
The monthly security cadence holds, but recent releases carry more of mailcow's own features and API changes alongside the upstream bumps. Breaking changes now come with explicit migration steps, which suggests the API is being cleaned up for integrators.
◆ Prediction
Expect the promised RCE advisory details next week and a lettered revision within weeks to address fallout from the sync job API and body-size changes.
Proton Bridge
2.5COMMS
Proton Bridge v3.27.2 adds support for the oo7 keyring on Linux.
◆ Current state
Proton Bridge's releases in 2026 have been almost entirely maintenance: monthly vulnerability patches, Go toolchain bumps, IMAP RFC-compliance fixes and recovery from corrupted sync state files. v3.27.2 adds one item, support for the oo7 keyring service, a Rust-based Secret Service implementation used on newer Linux desktops.
◆ Where it's heading
Bridge remains a stable compatibility layer rather than a growing product. The small additions that do land are about running cleanly on more desktop environments.
◆ Prediction
Expect the next monthly security patch release; the entries show no sign of feature work.
Alternatives to mailcow and Proton Bridge
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 Proton Bridge.
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Salesmsg
Salesmsg's Sherpa AI now sends replies and builds broadcasts on request, with approval first.
Netcore Cloud
Netcore keeps publishing unified-platform explainers with no product release.
Element
Element 1.12.34 RC.1 keeps call picture-in-picture and adds read receipts to the labs timeline.
See all mailcow alternatives → · See all Proton Bridge alternatives →
Recent activity from mailcow and Proton Bridge
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 3d agoProton Bridgev3.27.2: support for the oo7 keyring service
- 4d agomailcowMoovember 2026: admin RCE fix, mailbox groups, imapsync rework
- 19d agomailcow🎃🐮 Mooctober 2026 | Security Update: PHP 8.2.35, SOGo 5.12.12 & Nginx 1.30.6
- 1mo agomailcow2026-09a: Rspamd 4.2.1 and postfix-tlspol bumps
- 1mo agoProton Bridgev3.27.1: recover from corrupted sync state
- 1mo agomailcow🍂🐮 Mootember 2026 | Unbound 1.26.1, SOGo 5.12.11 & Redis 7.4.11
- 2mo agoProton Bridgev3.27.0: August security patches and IMAP fixes
- 2mo agomailcow🏖️🐮 Mooly 2026 | Postfix 3.10.12, Rspamd 4.1.0 & Nginx 1.30.3 - Revision B
- 2mo agoProton Bridgev3.26.0: July security patches and cleanup
- 3mo agomailcow🏖️🐮 Mooly 2026 | Postfix 3.10.12, Rspamd 4.1.0 & Nginx 1.30.3 - Revision A
- 5mo agoProton Bridgev3.25.0: clearer errors, legacy updater removed
- 6mo agoProton Bridgev3.24.2: new Go base image
Frequently asked questions
What is the difference between mailcow and Proton Bridge?
They serve adjacent needs but don't currently overlap on shipped themes. mailcow is currently shipping more aggressively (velocity 5.0 vs 2.5), with 0 editorial sparks in the last 30 days against 0. See the at-a-glance table above for a side-by-side breakdown of velocity, recent sparks, and editorial themes.
Is mailcow better than Proton Bridge?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. mailcow is currently shipping more aggressively (velocity 5.0 vs 2.5), with 0 editorial sparks in the last 30 days against 0. 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 Proton Bridge?
Top Proton Bridge alternatives in Comms are ranked by recent ship velocity. Browse the "Proton Bridge alternatives" section above for the current picks, or visit /alternatives/proton-bridge for the full list with editorial commentary on each.