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VerneMQ vs Stalwart

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

VerneMQ vs Stalwart: at a glance

FeatureVerneMQStalwart
SectorCommsComms
Velocity score2.56.3
Sparks · 30d01
Top themesmqtt, message-broker, clustering, websocketsemail-server, scim, jmap, enterprise-provisioning
Last editorial update1mo ago8d ago
WebsiteVisit →Visit →

What is VerneMQ?

VerneMQ's 2.2.0 collects a year of cluster and connection fixes into one release.

VerneMQ ships infrequently — the six most recent releases span February 2025 to August 2026 — and 2.2.0 on 9 August gathers roughly a year of accumulated work. Its contents are broker internals: a socket-accounting fix for rapid connect/disconnect churn, MQTT v5 property handling in the Lua auth cache, ETS-mirrored event subscriptions in the SWC metadata store, parallelised inter-node readiness checks, and anonymous-override extended to WebSocket listeners. The 2.1.3 release candidate from April was folded in and the version renumbered.

Read the full VerneMQ trajectory →

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.

Read the full Stalwart trajectory →

VerneMQ vs Stalwart: editorial side-by-side

V
VerneMQ
COMMS
2.5

VerneMQ's 2.2.0 collects a year of cluster and connection fixes into one release.

◆ Current state

VerneMQ ships infrequently — the six most recent releases span February 2025 to August 2026 — and 2.2.0 on 9 August gathers roughly a year of accumulated work. Its contents are broker internals: a socket-accounting fix for rapid connect/disconnect churn, MQTT v5 property handling in the Lua auth cache, ETS-mirrored event subscriptions in the SWC metadata store, parallelised inter-node readiness checks, and anonymous-override extended to WebSocket listeners. The 2.1.3 release candidate from April was folded in and the version renumbered.

◆ Where it's heading

Work concentrates on cluster behaviour and connection churn — the failure modes large MQTT fleets actually hit — rather than on protocol surface. Defaults are being revisited alongside the fixes: the retain-expiry check is now off by default and SWC initial sync is set to off, both choices that favour predictable behaviour on busy clusters over automatic housekeeping. Development stays maintainer-paced, with dependency bumps making up a visible share of each changelog, and the commercial EULA on binary packages continues to sit alongside the open source.

◆ Prediction

The next release is most likely another long-cycle collection of cluster and listener fixes rather than a feature line. Nothing in these entries points to a 3.0 direction.

S6.3

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.

Alternatives to VerneMQ and Stalwart

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 VerneMQ or Stalwart.

See all VerneMQ alternatives → · See all Stalwart alternatives →

Recent activity from VerneMQ and Stalwart

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

  1. 10d agoStalwartv0.16.21
  2. 17d agoStalwartv0.16.20
  3. 23d agoStalwartv0.16.19
  4. 1mo agoStalwartv0.16.18
  5. 1mo agoStalwartv0.16.17
  6. 1mo agoVerneMQSocket-count fix, WS(S) anonymous override, faster cluster readiness
  7. 1mo agoStalwartv0.16.16
  8. 4mo agoVerneMQTesting candidate later folded into 2.2.0
  9. 6mo agoVerneMQSUBACK error-path fix and routing-table memory reduction
  10. 11mo agoVerneMQSyslog boot fix and an HTTPS config regression from 2.1.0
  11. 1y agoVerneMQBreaking on-disk metadata format change
  12. 1y agoVerneMQRC3: bridge reconnect and inter-node connect options

Frequently asked questions

What is the difference between VerneMQ and Stalwart?

They serve adjacent needs but don't currently overlap on shipped themes. Stalwart is currently shipping more aggressively (velocity 6.3 vs 2.5), with 1 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 VerneMQ better than Stalwart?

Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. Stalwart is currently shipping more aggressively (velocity 6.3 vs 2.5), with 1 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 VerneMQ?

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

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.