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Comparison · Comms
Courier vs Rspamd
A side-by-side editorial comparison of Courier and Rspamd — release velocity, themes, recent moves, and the top alternatives to consider.
Courier vs Rspamd: at a glance
What is Courier?
Courier is turning its notification API into a full messaging orchestration platform.
Courier has evolved from a transactional notifications API into an orchestration platform anchored by Journeys, its event-driven workflow engine. Recent releases layer optimization and enterprise controls on top — A/B testing inside journeys, isolated environments, and reusable routing strategies. Design Studio has matured into the central authoring surface across email, SMS, push, in-app, and chat.
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.
Courier vs Rspamd: editorial side-by-side
Courier
5.0COMMS
Courier is turning its notification API into a full messaging orchestration platform.
◆ Current state
Courier has evolved from a transactional notifications API into an orchestration platform anchored by Journeys, its event-driven workflow engine. Recent releases layer optimization and enterprise controls on top — A/B testing inside journeys, isolated environments, and reusable routing strategies. Design Studio has matured into the central authoring surface across email, SMS, push, in-app, and chat.
◆ Where it's heading
The build order is clear: ship the orchestration core first (Journeys, Design Studio, the MCP-aware CLI), then make it production-grade for larger teams. The last quarter is about optimization and governance — experiments, custom environments, decoupled routing — rather than net-new channels. AI is being threaded in as a feature, like localization, not a headline product.
◆ Prediction
Expect continued hardening of Journeys as the hub: more experiment types, richer per-variant analytics, and deeper AI assistance inside Design Studio.
Rspamd
5.0COMMS
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 Courier 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 Courier or Rspamd.
Salesmsg
Salesmsg adds call-back requests and a one-click Emergency Stop for all outbound texts.
Element
Element 1.12.35 follows the call picture-in-picture release with one desktop storage fix.
Krisp
Krisp moves call transcripts and live captions to cloud transcription in KrispCX 2.84.4.
Misskey
Misskey 2026.11 ships: a leaner start script, and Node.js 22 no longer boots.
SlickText
SlickText's feed is all SMS buying guides; no product release has surfaced since RCS.
See all Courier alternatives → · See all Rspamd alternatives →
Recent activity from Courier and Rspamd
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 22h agoRspamd4.3.0: SPF order fix, stricter DKIM, new truncation symbols
- 24d agoRspamd4.2.3: ARC trust fix, merged RBL queries, browser-style HTML parsing
- 1mo agoRspamd4.2.2: crypto wallet detection and changed MIME digests
- 1mo agoRspamd4.2.1: critical HTTP and memory-safety fixes
- 1mo agoRspamd4.2.0: public suffix lookup and attachment content extraction
- 3mo agoRspamdCloses an arbitrary file read reachable by any TCP client
- 4mo agoCourierExperiments: A/B Testing in Journeys
- 4mo agoCourierAI Localization
- 5mo agoCourierEmbed Notification Preferences with One Web Component
- 5mo agoCourierIntroducing Routing: Reusable Strategies for Every Template
- 6mo agoCourierEmail Fonts and Colors
- 6mo agoCourierCustom Environments for Safer Messaging Workflows
Frequently asked questions
What is the difference between Courier and Rspamd?
They serve adjacent needs but don't currently overlap on shipped themes. Courier 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 Courier better than Rspamd?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. Courier 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 Courier?
Top Courier alternatives in Comms are ranked by recent ship velocity. Browse the "Courier alternatives" section above for the current picks, or visit /alternatives/courier 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.