Fonoster
Fonoster ships four releases in a day to make linking a Twilio number a single step.
Comparison · Comms
Stalwart vs Synapse
A side-by-side editorial comparison of Stalwart and Synapse — release velocity, themes, recent moves, and the top alternatives to consider.
Shared themes:self-hosted
Stalwart vs Synapse: at a glance
What is Stalwart?
Stalwart adds full SCIM v2 provisioning and 24-language calendar support as its standards coverage extends further than most commercial mail servers.
Stalwart is maintaining a weekly-or-faster release cadence, with alternating feature releases and dense bug-fix releases. The v0.16.20 release landed full SCIM v2 (Enterprise) including cursor-based pagination and the IPSIE lifecycle profile, conference links in calendar invites, and 24 new calendar interface translations. Below the feature line, the project is steadily closing correctness gaps across JMAP, CalDAV, IMAP, and MTA — many of them edge-case RFC compliance issues.
What is Synapse?
Synapse maintains its reliable biweekly release cadence with stable v1.159 and v1.160 following a multi-fix security release in v1.157.2.
Synapse (Matrix homeserver, maintained by Element) follows a disciplined release cadence: RC1 → RC2 → stable, cycling approximately every two weeks. The most operationally significant recent event was v1.157.2 — a dedicated security release patching four high-severity and multiple moderate/low-severity vulnerabilities, with explicit guidance for open-federation homeservers to upgrade promptly. Subsequent v1.158–v1.160 releases continue the regular cadence; changelogs are externally hosted on GitHub.
Stalwart vs Synapse: editorial side-by-side
Stalwart
6.3COMMS
Stalwart adds full SCIM v2 provisioning and 24-language calendar support as its standards coverage extends further than most commercial mail servers.
◆ Current state
Stalwart is maintaining a weekly-or-faster release cadence, with alternating feature releases and dense bug-fix releases. The v0.16.20 release landed full SCIM v2 (Enterprise) including cursor-based pagination and the IPSIE lifecycle profile, conference links in calendar invites, and 24 new calendar interface translations. Below the feature line, the project is steadily closing correctness gaps across JMAP, CalDAV, IMAP, and MTA — many of them edge-case RFC compliance issues.
◆ Where it's heading
Stalwart is building toward parity with commercial enterprise mail servers on identity federation and provisioning (SCIM v2, VAPID for web push, DMARCbis/DKIM2 already landed). The pace of RFC implementation is unusually aggressive for an open-source project; the combination of JMAP, CalDAV, IMAP UIDONLY/UIDBATCHES, and SCIM v2 positions it as a viable self-hosted alternative for organizations that need standards compliance without vendor lock-in.
◆ Prediction
WebAuthn/passkey-based authentication and improved multi-tenant administration tooling are the most likely next capability additions, given the current trajectory toward enterprise identity management.
Synapse
5.0COMMS
Synapse maintains its reliable biweekly release cadence with stable v1.159 and v1.160 following a multi-fix security release in v1.157.2.
◆ Current state
Synapse (Matrix homeserver, maintained by Element) follows a disciplined release cadence: RC1 → RC2 → stable, cycling approximately every two weeks. The most operationally significant recent event was v1.157.2 — a dedicated security release patching four high-severity and multiple moderate/low-severity vulnerabilities, with explicit guidance for open-federation homeservers to upgrade promptly. Subsequent v1.158–v1.160 releases continue the regular cadence; changelogs are externally hosted on GitHub.
◆ Where it's heading
Synapse's changelog pattern reflects a mature, infrastructure-grade project prioritizing stability and security over feature velocity. The security release cadence (v1.157.2 dropped between regular stable releases) suggests the security team is actively monitoring CVEs in the federated deployment context. Without changelogs embedded in entries, the magnitude of each stable release is hard to assess, but the rhythm itself signals a team focused on operational reliability.
◆ Prediction
v1.161.0 stable (currently in RC) will follow the same pattern; the next meaningful development to watch is whether Element ships any MLS (Messaging Layer Security) or MIMI (More Instant Messaging Interoperability) progress in the v1.16x range.
Alternatives to Stalwart 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 Stalwart or Synapse.
Element
Element 1.12.33 ships: simpler recovery keys, mandatory verification, no libolm migration.
Tawk.to
tawk.to's widget 4.4.0 turns to keyboard and screen-reader fixes after a run of form work.
Krisp
Krisp 2.83.4 brings Voice Translation into conference calls and lightens Accent Conversion.
Pixelfed
Pixelfed 0.15.2 ships the PHP RCE patches and turns cached timelines on for everyone.
Salesmsg
Salesmsg Reviews can now trigger follow-ups automatically based on a customer's latest rating.
See all Stalwart alternatives → · See all Synapse alternatives →
Recent activity from Stalwart and Synapse
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 1mo agoSynapseSynapse v1.161.0 Release Candidate 1
- 1mo agoStalwartv0.16.21
- 1mo agoSynapseSynapse v1.160.0 stable release
- 1mo agoSynapseSynapse v1.160.0 Release Candidate 2
- 2mo agoStalwartv0.16.20 ⚡
- 2mo agoSynapseSynapse v1.160.0 Release Candidate 1
- 2mo agoStalwartv0.16.19
- 2mo agoSynapseSynapse v1.159.0 stable release
- 2mo agoStalwartv0.16.18
- 2mo agoSynapseSynapse v1.159.0 Release Candidate 1
- 2mo agoStalwartv0.16.17
- 2mo agoStalwartv0.16.16
Frequently asked questions
What is the difference between Stalwart and Synapse?
Both compete on the same themes — self-hosted — within Comms. Stalwart is currently shipping more aggressively (velocity 6.3 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 Synapse?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. Stalwart is currently shipping more aggressively (velocity 6.3 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 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.