← Back to home
Comparison · Infra & APIs

Prometheus Alertmanager vs Gloo Gateway

A side-by-side editorial comparison of Prometheus Alertmanager and Gloo Gateway — release velocity, themes, recent moves, and the top alternatives to consider.

Prometheus Alertmanager vs Gloo Gateway: at a glance

FeaturePrometheus AlertmanagerGloo Gateway
SectorInfra & APIsInfra & APIs
Velocity score2.55.0
Sparks · 30d00
Top themesalerting, prometheus, observability, breaking-changesapi-gateway, maintenance, kubernetes, envoy
Last editorial update2h ago1h ago
WebsiteVisit →Visit →

What is Prometheus Alertmanager?

Alertmanager 0.34.2 turns off CORS by default, breaking cross-origin API calls.

Alertmanager handles deduplication, grouping, silencing and routing of Prometheus alerts. 0.34.2 (October 29) stops sending CORS headers by default, so cross-origin calls to api/v2 now fail unless --web.cors.origin is set, and rebuilds with Go 1.26.10 to distrust the compromised eMudhra intermediates. 0.34.1 fixed inhibitions that could un-mute alerts, and 0.34.0 split auth and rate-limit failures out of the clientError metric reason.

Read the full Prometheus Alertmanager trajectory →

What is Gloo Gateway?

Gloo Gateway's October batch fixes proxies that silently kept stale endpoints.

Gloo Gateway still maintains 1.19, 1.20 and 1.21 in parallel and releases them in same-day batches. The 2026-10-21 batch fixes a bug where a placeholder EDS assignment carried the wrong cluster name, so a proxy received an update it could not match, kept its old endpoints and never recovered. Each line also moved to Go 1.26.10; 1.21 additionally upgraded kin-openapi.

Read the full Gloo Gateway trajectory →

Prometheus Alertmanager vs Gloo Gateway: editorial side-by-side

P2.5

Alertmanager 0.34.2 turns off CORS by default, breaking cross-origin API calls.

◆ Current state

Alertmanager handles deduplication, grouping, silencing and routing of Prometheus alerts. 0.34.2 (October 29) stops sending CORS headers by default, so cross-origin calls to api/v2 now fail unless --web.cors.origin is set, and rebuilds with Go 1.26.10 to distrust the compromised eMudhra intermediates. 0.34.1 fixed inhibitions that could un-mute alerts, and 0.34.0 split auth and rate-limit failures out of the clientError metric reason.

◆ Where it's heading

The 0.3x line keeps shipping breaking changes outside major versions: metric reason splits in 0.34.0, per-group markers in 0.33.0 and now a CORS default in a patch. Operators need to read every release note, not just minors.

◆ Prediction

Expect 0.35.0 to carry further breaking changes in the vein of 0.33 and 0.34, though the entries do not say what it will contain.

G
Gloo Gateway
INFRA · APIS
5.0

Gloo Gateway's October batch fixes proxies that silently kept stale endpoints.

◆ Current state

Gloo Gateway still maintains 1.19, 1.20 and 1.21 in parallel and releases them in same-day batches. The 2026-10-21 batch fixes a bug where a placeholder EDS assignment carried the wrong cluster name, so a proxy received an update it could not match, kept its old endpoints and never recovered. Each line also moved to Go 1.26.10; 1.21 additionally upgraded kin-openapi.

◆ Where it's heading

Releases remain maintenance: Go and Kubernetes bumps on a weekly rhythm, with an occasional real bug fix shipped to every line at once. The 1.18 line no longer appears in the October batches. No new features are visible.

◆ Prediction

Expect further same-day dependency batches across the three lines; the entries show no feature release coming.

Alternatives to Prometheus Alertmanager and Gloo Gateway

Other Infra & APIs 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 Prometheus Alertmanager or Gloo Gateway.

See all Prometheus Alertmanager alternatives → · See all Gloo Gateway alternatives →

Recent activity from Prometheus Alertmanager and Gloo Gateway

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

  1. 4d agoPrometheus Alertmanager0.34.2: CORS off by default, eMudhra CAs distrusted
  2. 11d agoGloo GatewayFix for proxies stuck on stale endpoints; Go 1.26.10
  3. 11d agoGloo Gateway1.20 backport of the stale-endpoint fix; Go 1.26.10
  4. 11d agoGloo Gateway1.19 backport of the stale-endpoint fix; Go 1.26.10
  5. 17d agoGloo Gateway1.20.27 bumps Go to 1.26.9
  6. 17d agoGloo Gateway1.21.18 bumps Go to 1.26.9
  7. 17d agoGloo Gateway1.19.25 bumps Go to 1.26.9
  8. 1mo agoPrometheus Alertmanager0.34.1: inhibition fixes stop alerts being wrongly un-muted
  9. 2mo agoPrometheus AlertmanagerNotification failure reasons split; templatable route labels added
  10. 4mo agoPrometheus AlertmanagerSilence snapshot legacy matchers field restored
  11. 4mo agoPrometheus AlertmanagerPer-group alert markers replace the global one; event recorder lands ⚡
  12. 4mo agoPrometheus AlertmanagerDispatcher goroutine leak on alertgroup swap fixed

Frequently asked questions

What is the difference between Prometheus Alertmanager and Gloo Gateway?

They serve adjacent needs but don't currently overlap on shipped themes. Gloo Gateway is currently shipping more aggressively (velocity 5.0 vs 2.5), 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 Prometheus Alertmanager better than Gloo Gateway?

Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. Gloo Gateway is currently shipping more aggressively (velocity 5.0 vs 2.5), with 0 editorial sparks in the last 30 days against 0. For your specific use case, the alternatives sections above list other Infra & APIs products to evaluate alongside.

What are the best alternatives to Prometheus Alertmanager?

Top Prometheus Alertmanager alternatives in Infra & APIs are ranked by recent ship velocity. Browse the "Prometheus Alertmanager alternatives" section above for the current picks, or visit /alternatives/alertmanager for the full list with editorial commentary on each.

What are the best alternatives to Gloo Gateway?

Top Gloo Gateway alternatives in Infra & APIs are ranked by recent ship velocity. Browse the "Gloo Gateway alternatives" section above for the current picks, or visit /alternatives/gloo for the full list with editorial commentary on each.