Prometheus Alertmanager vs ESPHome

Alertmanager handles deduplication, grouping, silencing and routing of alerts from Prometheus. The 0.34.0 release adds templatable labels on alert routes, server-side state filters on the silences API, and splits authError and rateLimited out of the generic clientError reason on the notification failure metric — a change that breaks any dashboard or alert matching reason="clientError" for 401, 403 or 429 responses.

The last three minor releases show a project willing to break its own surfaces to fix its structure. Version 0.33.0 replaced the global alert marker with per-aggregation-group markers, removed the alertmanager_marked_alerts metric, and moved several types out of public packages; 0.34.0 continues by making a metric label more precise at the cost of existing queries. The structured event recorder, introduced behind a feature flag in 0.33.0, keeps accumulating output types and detail, which is the clearest signal of intent here — Alertmanager is building a first-class record of its own routing decisions.

The event recorder is the thread most likely to advance next, given it has gained outputs and event detail in each of the last two releases and remains behind a feature flag. Expect it to stabilise before the flag comes off.