Maddy
A one-binary mail server learning to behave like production infrastructure.
Comparison · Comms
mailcow vs Stalwart
A side-by-side editorial comparison of mailcow and Stalwart — release velocity, themes, recent moves, and the top alternatives to consider.
Shared themes:mail-serverself-hosted
mailcow vs Stalwart: 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 Stalwart?
Stalwart keeps chasing standards nobody has implemented yet — DKIM2, DMARCbis, now JMAP email push.
Stalwart is a single-binary mail and collaboration server covering JMAP, IMAP, SMTP, CalDAV and CardDAV. The 0.16.x line ships roughly weekly and its additions cluster in one place: implementing IETF drafts and fresh RFCs ahead of the field, while a long tail of JMAP conformance and MTA edge-case fixes runs underneath. The latest release adds JMAP email delivery push notifications, completing a push stack built across the last three releases.
mailcow vs Stalwart: 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.
Stalwart
5.0COMMS
Stalwart keeps chasing standards nobody has implemented yet — DKIM2, DMARCbis, now JMAP email push.
◆ Current state
Stalwart is a single-binary mail and collaboration server covering JMAP, IMAP, SMTP, CalDAV and CardDAV. The 0.16.x line ships roughly weekly and its additions cluster in one place: implementing IETF drafts and fresh RFCs ahead of the field, while a long tail of JMAP conformance and MTA edge-case fixes runs underneath. The latest release adds JMAP email delivery push notifications, completing a push stack built across the last three releases.
◆ Where it's heading
The push story is the clearest arc: Web Push payload and subscription fixes in 0.16.10, VAPID per RFC 9749 in 0.16.14, and the emailpush draft in 0.16.16. Parallel to it, 0.16.12 landed DKIM2 and the DMARCbis trio, and the fix lists keep narrowing toward strict-spec behaviour — DMARC alignment reporting, SMTP line-length limits, BDAT error codes. Stalwart is positioning as the reference implementation of modern mail standards rather than competing on features.
◆ Prediction
Expect the JMAP push work to keep filling in — subscription lifecycle, delivery semantics — alongside continued DKIM2 and DMARCbis refinement as those drafts move. The fix cadence suggests operational hardening around clustering and Redis locking is the other near-term thread.
Alternatives to mailcow and Stalwart
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 Stalwart.
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 Stalwart alternatives →
Recent activity from mailcow and Stalwart
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 16h agoStalwartv0.16.16 — JMAP email push, plus Redis lock and SMTP relay fixes
- 4d agomailcow🏖️🐮 Mooly 2026 | Postfix 3.10.12, Rspamd 4.1.0 & Nginx 1.30.3 - Revision A
- 7d agoStalwartv0.16.15 — JMAP, MTA, and auth privilege fixes
- 13d agoStalwartv0.16.14 — VAPID Web Push plus push and calendar fixes
- 21d agomailcow🏖️🐮 Mooly 2026 | Postfix 3.10.12, Rspamd 4.1.0 & Nginx 1.30.3
- 21d agoStalwartv0.16.13 — FreeBSD support and OAuth/JMAP fixes
- 27d agoStalwartv0.16.12 — DKIM2 and DMARCbis email-authentication support
- 1mo agoStalwartv0.16.11 — S/MIME encryption-at-rest and Redis Sentinel backend
- 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 Stalwart?
Both compete on the same themes — mail-server, self-hosted — within Comms. mailcow and Stalwart 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 Stalwart?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. mailcow and Stalwart 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 Stalwart?
Top Stalwart alternatives in Comms are ranked by recent ship velocity. Browse the "Stalwart alternatives" section above for the current picks, or visit /alternatives/stalwart for the full list with editorial commentary on each.