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mailcow vs Rspamd

A side-by-side editorial comparison of mailcow and Rspamd — release velocity, themes, recent moves, and the top alternatives to consider.

mailcow vs Rspamd: at a glance

FeaturemailcowRspamd
SectorCommsComms
Velocity score5.05.0
Sparks · 30d00
Top themesmail-server, self-hosted, security-updates, breaking-changesspam filtering, email authentication, input hardening, attachment extraction
Last editorial update8d ago3h ago
WebsiteVisit →Visit →

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.

Read the full mailcow trajectory →

What is Rspamd?

Rspamd 4.3 fixes SPF evaluation order and rejects weak DKIM keys, with results that change.

Rspamd 4.3.0 on November 13 is a correctness release with a long incompatible-changes list. SPF records are now evaluated in term order, closing a case where an explicit -ip4 deny could be overridden by a broader allow. DKIM rejects RSA keys under 1024 bits and signatures with duplicate tags, DMARC no longer drops a policy over an unknown tag, URL mismatches are scored apart from phishing, and PDF text extraction and archive unpacking change their output. Critical fixes cover a header line that could abort a worker from one unauthenticated HTTP request.

Read the full Rspamd trajectory →

mailcow vs Rspamd: editorial side-by-side

M
mailcow
COMMS
5.0

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.

R
Rspamd
COMMS
5.0

Rspamd 4.3 fixes SPF evaluation order and rejects weak DKIM keys, with results that change.

◆ Current state

Rspamd 4.3.0 on November 13 is a correctness release with a long incompatible-changes list. SPF records are now evaluated in term order, closing a case where an explicit -ip4 deny could be overridden by a broader allow. DKIM rejects RSA keys under 1024 bits and signatures with duplicate tags, DMARC no longer drops a policy over an unknown tag, URL mismatches are scored apart from phishing, and PDF text extraction and archive unpacking change their output. Critical fixes cover a header line that could abort a worker from one unauthenticated HTTP request.

◆ Where it's heading

Since 4.1, every release has hardened parsers and closed memory-safety and trust gaps; 4.3 applies the same pass to the authentication standards themselves (SPF, DKIM, DMARC, ARC) and to content extraction. Operators should expect scores and fuzzy hashes to shift after upgrading, because the project now favours spec-correct results over backward-compatible ones.

◆ Prediction

A 4.3.x point release fixing regressions from these behaviour changes is the likely next step, as 4.2.1 followed 4.2.0 within two weeks.

Alternatives to mailcow and Rspamd

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 Rspamd.

See all mailcow alternatives → · See all Rspamd alternatives →

Recent activity from mailcow and Rspamd

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

  1. 22h agoRspamd4.3.0: SPF order fix, stricter DKIM, new truncation symbols
  2. 9d agomailcowMoovember 2026: admin RCE fix, mailbox groups, imapsync rework
  3. 23d agomailcow🎃🐮 Mooctober 2026 | Security Update: PHP 8.2.35, SOGo 5.12.12 & Nginx 1.30.6
  4. 24d agoRspamd4.2.3: ARC trust fix, merged RBL queries, browser-style HTML parsing
  5. 1mo agoRspamd4.2.2: crypto wallet detection and changed MIME digests
  6. 1mo agomailcow2026-09a: Rspamd 4.2.1 and postfix-tlspol bumps
  7. 1mo agoRspamd4.2.1: critical HTTP and memory-safety fixes
  8. 1mo agomailcow🍂🐮 Mootember 2026 | Unbound 1.26.1, SOGo 5.12.11 & Redis 7.4.11
  9. 1mo agoRspamd4.2.0: public suffix lookup and attachment content extraction
  10. 2mo agomailcow🏖️🐮 Mooly 2026 | Postfix 3.10.12, Rspamd 4.1.0 & Nginx 1.30.3 - Revision B
  11. 3mo agoRspamdCloses an arbitrary file read reachable by any TCP client
  12. 3mo agomailcow🏖️🐮 Mooly 2026 | Postfix 3.10.12, Rspamd 4.1.0 & Nginx 1.30.3 - Revision A

Frequently asked questions

What is the difference between mailcow and Rspamd?

They serve adjacent needs but don't currently overlap on shipped themes. mailcow and Rspamd 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 Rspamd?

Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. mailcow and Rspamd 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 Rspamd?

Top Rspamd alternatives in Comms are ranked by recent ship velocity. Browse the "Rspamd alternatives" section above for the current picks, or visit /alternatives/rspamd for the full list with editorial commentary on each.