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Rspamd vs Synapse

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

Rspamd vs Synapse: at a glance

FeatureRspamdSynapse
SectorCommsComms
Velocity score5.05.0
Sparks · 30d00
Top themesspam filtering, email authentication, input hardening, attachment extractionmatrix, self-hosting, release-cadence, messaging-infrastructure
Last editorial update3h ago2d ago
WebsiteVisit →Visit →

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 →

What is Synapse?

Synapse keeps a fixed release train: one minor a fortnight, patches in between.

Synapse, the Matrix homeserver from Element, shipped 1.164 and 1.165 within three weeks, each after release candidates, plus three 1.164 and two 1.163 patch releases. The captured entries only link to CHANGES.md, so the feed shows the cadence but not what changed for operators.

Read the full Synapse trajectory →

Rspamd vs Synapse: editorial side-by-side

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.

S
Synapse
COMMS
5.0

Synapse keeps a fixed release train: one minor a fortnight, patches in between.

◆ Current state

Synapse, the Matrix homeserver from Element, shipped 1.164 and 1.165 within three weeks, each after release candidates, plus three 1.164 and two 1.163 patch releases. The captured entries only link to CHANGES.md, so the feed shows the cadence but not what changed for operators.

◆ Where it's heading

The pattern is a predictable train: release candidates about a week before each stable minor, and quick patches on the current and previous branch. Without the changelog text in the feed, it is unclear whether these releases carry new features or mostly fixes and maintenance.

◆ Prediction

A 1.166.0rc1 is likely within about two weeks, following the same rc-then-stable pattern; its content can't be predicted from these entries.

Alternatives to Rspamd 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 Rspamd or Synapse.

See all Rspamd alternatives → · See all Synapse alternatives →

Recent activity from Rspamd and Synapse

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

  1. 21h agoRspamd4.3.0: SPF order fix, stricter DKIM, new truncation symbols
  2. 3d agoSynapseSynapse 1.165 reaches stable
  3. 9d agoSynapseSynapse 1.165 release candidate 1
  4. 11d agoSynapseSynapse 1.164.2 patch release
  5. 16d agoSynapseSynapse 1.164.1 patch release
  6. 17d agoSynapseSynapse 1.164 reaches stable after three RCs
  7. 21d agoSynapseSynapse 1.164 release candidate 3
  8. 24d agoRspamd4.2.3: ARC trust fix, merged RBL queries, browser-style HTML parsing
  9. 1mo agoRspamd4.2.2: crypto wallet detection and changed MIME digests
  10. 1mo agoRspamd4.2.1: critical HTTP and memory-safety fixes
  11. 1mo agoRspamd4.2.0: public suffix lookup and attachment content extraction
  12. 3mo agoRspamdCloses an arbitrary file read reachable by any TCP client

Frequently asked questions

What is the difference between Rspamd and Synapse?

They serve adjacent needs but don't currently overlap on shipped themes. Rspamd 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 Rspamd better than Synapse?

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

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.