Betaflight
Betaflight grew a real autopilot: waypoint missions, geofence RTH and MAVLink ground control
Comparison · DevOps
Undertow vs Z-Wave JS
A side-by-side editorial comparison of Undertow and Z-Wave JS — release velocity, themes, recent moves, and the top alternatives to consider.
Undertow vs Z-Wave JS: at a glance
What is Undertow?
Undertow 2.4.0 clears three CVEs and finally lands long-open HTTP/2 and timeout requests
Undertow's 2.4 line opened in May 2026 with a release that combines three CVE fixes with a backlog of feature requests, several of them years old judging by their issue numbers — in-flight request processing time tracking, comments in the predicate language, a configurable async context timeout replacing a hard-coded one, HTTP/2 GOAWAY connection management, a TLS protocol version exchange attribute, and a method to invalidate all cache paths. The two releases since have been small: a handful of Jiras in 2.4.1, and a 2.4.2 whose entire release note is the sentence that it was tagged.
What is Z-Wave JS?
Z-Wave driver where the hard problems are now smart locks and device quirks.
Z-Wave JS is the driver layer underneath most open-source Z-Wave integrations, and its releases follow a tight weekly-to-fortnightly rhythm mixing three things: protocol correctness, device config files, and developer surface. The current focus is clearly credential handling on smart locks — several consecutive releases fix stale cached credentials, bulk user deletion timeouts, and locks misreporting progress during credential learning. Alongside that, inclusion reliability got direct attention, with ongoing interviews now paused during inclusion and security bootstrapping.
Undertow vs Z-Wave JS: editorial side-by-side
Undertow
0.0DEVOPS
Undertow 2.4.0 clears three CVEs and finally lands long-open HTTP/2 and timeout requests
◆ Current state
Undertow's 2.4 line opened in May 2026 with a release that combines three CVE fixes with a backlog of feature requests, several of them years old judging by their issue numbers — in-flight request processing time tracking, comments in the predicate language, a configurable async context timeout replacing a hard-coded one, HTTP/2 GOAWAY connection management, a TLS protocol version exchange attribute, and a method to invalidate all cache paths. The two releases since have been small: a handful of Jiras in 2.4.1, and a 2.4.2 whose entire release note is the sentence that it was tagged.
◆ Where it's heading
The 2.4.0 pattern — a long-deferred feature backlog shipping in the same release as security fixes — suggests features move when a release has to happen anyway rather than on their own schedule. What did ship points at operational control: timeouts that were hard-coded becoming configurable, connection lifecycle handling for HTTP/2, and attributes exposing TLS and timing detail to whatever sits above the server. Enabling test runs on JDK 25 in 2.4.1 is the only forward-looking item in the two follow-up releases.
◆ Prediction
With three entries and one substantive release among them, there is little to extrapolate from; the JDK 25 test enablement is the one thread that implies more work, pointing at runtime compatibility rather than features as the near-term focus.
Z-Wave JS
5.0DEVOPS
Z-Wave driver where the hard problems are now smart locks and device quirks.
◆ Current state
Z-Wave JS is the driver layer underneath most open-source Z-Wave integrations, and its releases follow a tight weekly-to-fortnightly rhythm mixing three things: protocol correctness, device config files, and developer surface. The current focus is clearly credential handling on smart locks — several consecutive releases fix stale cached credentials, bulk user deletion timeouts, and locks misreporting progress during credential learning. Alongside that, inclusion reliability got direct attention, with ongoing interviews now paused during inclusion and security bootstrapping.
◆ Where it's heading
The protocol work is moving from getting commands through to getting them right under adversarial timing — S2 delivery verification, split multi-frame reports, and optimistic value updates now distinguishing actuator from non-actuator command classes. The other steady stream is the device database, which absorbs manufacturer inconsistencies so integrations above it do not have to.
◆ Prediction
User Code and User Credential handling should keep generating fixes, since each release surfaces another lock firmware that deviates from the spec in a new way.
Alternatives to Undertow and Z-Wave JS
Other DevOps 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 Undertow or Z-Wave JS.
OceanBase
OceanBase is rebuilding itself as a RAG backend without giving up the HTAP story
QGroundControl
QGroundControl rebuilt its flight UI around touch screens, then went quiet for ten months
Pelican
Pelican now ships roughly once a year, and 4.12 is theme housekeeping
WildFly
WildFly's quarterly train is really a stability ladder, and OIDC keeps climbing it
RESTEasy
Jakarta REST implementation in pure maintenance across two parallel branches.
See all Undertow alternatives → · See all Z-Wave JS alternatives →
Recent activity from Undertow and Z-Wave JS
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 4d agoZ-Wave JSPTI Zniffer trace support and a value-DB race condition fix
- 25d agoZ-Wave JSInterviews pause during inclusion; proprietary Aeotec and Z-Wave.me commands
- 1mo agoZ-Wave JSMissing type exports and command class metadata corrections
- 1mo agoZ-Wave JSS2 delivery verification via sequence number; User Code cache sync fix
- 1mo agoZ-Wave JSDevice config corrections for Zooz, SimonTech and MCOHome
- 1mo agoUndertow2.4.2.Final
- 1mo agoZ-Wave JSGranular interview progress reporting via a new event
- 2mo agoUndertowUndertow 2.4.1 makes the HTTP/1.1 reason-phrase optional
- 2mo agoUndertowUndertow 2.4.0 fixes three CVEs and adds HTTP/2 GOAWAY handling
Frequently asked questions
What is the difference between Undertow and Z-Wave JS?
They serve adjacent needs but don't currently overlap on shipped themes. Z-Wave JS is currently shipping more aggressively (velocity 5.0 vs 0.0), 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 Undertow better than Z-Wave JS?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. Z-Wave JS is currently shipping more aggressively (velocity 5.0 vs 0.0), with 0 editorial sparks in the last 30 days against 0. For your specific use case, the alternatives sections above list other DevOps products to evaluate alongside.
What are the best alternatives to Undertow?
Top Undertow alternatives in DevOps are ranked by recent ship velocity. Browse the "Undertow alternatives" section above for the current picks, or visit /alternatives/undertow for the full list with editorial commentary on each.
What are the best alternatives to Z-Wave JS?
Top Z-Wave JS alternatives in DevOps are ranked by recent ship velocity. Browse the "Z-Wave JS alternatives" section above for the current picks, or visit /alternatives/zwave-js for the full list with editorial commentary on each.