Rspamd
Rspamd 4.3 fixes SPF evaluation order and rejects weak DKIM keys, with results that change.
Comparison · Comms
Stalwart vs Fonoster
A side-by-side editorial comparison of Stalwart and Fonoster — release velocity, themes, recent moves, and the top alternatives to consider.
Stalwart vs Fonoster: at a glance
What is Stalwart?
Stalwart's weekly releases have turned from new standards to correctness fixes.
Stalwart's releases since v0.16.20 are dominated by long Fixed lists across IMAP, JMAP, MTA, DMARC and iTIP. Additions have been small: a PowerDNS provider in 0.16.24, sd_notify and JMAP mailbox behavior in 0.16.26. The most consequential repair is a RocksDB bug in 0.16.26 that rewrote every stored blob on each compaction of the blobs column family, about once per 128MB of new mail.
What is Fonoster?
Fonoster now cleans up deleted workspaces and stops exposing stored secrets.
Fonoster ships minor versions almost daily. v0.51 to v0.53 added Anthropic, Google and Groq models, TTS voice choice and one-switch call recording. From November 10, v0.54 to v0.56 added branded emails, legal pages, webhook event lookups and API key rotation, and v0.57 returns secret values only to API keys, cancels a deleted user's plan, and ends a deleted workspace's calls and resources.
Stalwart vs Fonoster: editorial side-by-side
Stalwart
5.0COMMS
Stalwart's weekly releases have turned from new standards to correctness fixes.
◆ Current state
Stalwart's releases since v0.16.20 are dominated by long Fixed lists across IMAP, JMAP, MTA, DMARC and iTIP. Additions have been small: a PowerDNS provider in 0.16.24, sd_notify and JMAP mailbox behavior in 0.16.26. The most consequential repair is a RocksDB bug in 0.16.26 that rewrote every stored blob on each compaction of the blobs column family, about once per 128MB of new mail.
◆ Where it's heading
After the SCIM v2 release in August, the project has shifted from extending coverage to making existing coverage hold up under real use. The bug reports now describe specific interoperability cases, such as Apple Calendar duplicates and DMARC report formatting, which suggests production traffic is driving the queue. The weekly cadence itself has not changed.
◆ Prediction
Expect more weekly fix releases on the same pattern. The entries show no sign of the next major capability, so its timing is unclear.
Fonoster
7.5COMMS
Fonoster now cleans up deleted workspaces and stops exposing stored secrets.
◆ Current state
Fonoster ships minor versions almost daily. v0.51 to v0.53 added Anthropic, Google and Groq models, TTS voice choice and one-switch call recording. From November 10, v0.54 to v0.56 added branded emails, legal pages, webhook event lookups and API key rotation, and v0.57 returns secret values only to API keys, cancels a deleted user's plan, and ends a deleted workspace's calls and resources.
◆ Where it's heading
After a quick run of voice-AI options, Fonoster has turned to what a hosted service needs before paying customers rely on it: legal pages, billing correctness, webhook debugging and account deletion that actually removes data. The cadence stays daily and the changes stay incremental.
◆ Prediction
More account and billing lifecycle work is likely next, since v0.57 adds a billing test case and deletion rules in the same release.
Alternatives to Stalwart and Fonoster
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 Stalwart or Fonoster.
Twilio
Twilio's voice AI stops cutting callers off mid-sentence, using its own turn-taking model.
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.
See all Stalwart alternatives → · See all Fonoster alternatives →
Recent activity from Stalwart and Fonoster
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 3d agoFonosterv0.57: secrets locked to API keys, full cleanup on account deletion
- 3d agoFonosterv0.56: webhook event bodies visible, API key regenerate becomes rotate
- 3d agoFonosterFonoster v0.55 shows the event each webhook delivery sent
- 3d agoFonosterFonoster v0.54.1 stops gather cutting off early answers
- 3d agoFonosterFonoster v0.54 adds branded emails and legal pages
- 5d agoFonosterFonoster v0.53 adds one-switch call recording and credit usage
- 26d agoStalwartv0.16.27: IMAP SEARCH RETURN and iTIP time zone fixes
- 1mo agoStalwartv0.16.26 fixes RocksDB rewriting every blob on compaction
- 1mo agoStalwartv0.16.25: JMAP MaskedEmail and Autodiscover fixes
- 1mo agoStalwartv0.16.24: PowerDNS provider and phishing list matching fix
- 1mo agoStalwartv0.16.23: nested list delivery and lost DSN fixes
- 2mo agoStalwartv0.16.22: STARTTLS session reset and DMARC result fixes
Frequently asked questions
What is the difference between Stalwart and Fonoster?
They serve adjacent needs but don't currently overlap on shipped themes. Fonoster is currently shipping more aggressively (velocity 7.5 vs 5.0), 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 Stalwart better than Fonoster?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. Fonoster is currently shipping more aggressively (velocity 7.5 vs 5.0), 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 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.
What are the best alternatives to Fonoster?
Top Fonoster alternatives in Comms are ranked by recent ship velocity. Browse the "Fonoster alternatives" section above for the current picks, or visit /alternatives/fonoster for the full list with editorial commentary on each.