Best observability tools (2026)

1. 1.Uptime KumaMIT self-host uptime monitoring and status pages

   Free / OSS · OSS/MIT · 92.6k GitHub stars

   VerdictMIT self-host uptime. Free forever; you own the box on 3001.

   CatchSelf-host uptime + status pages — not Datadog/APM. You run the container, backups, and alerting path. HTTP/TCP checks are the lane, not full distributed tracing.

2. 2.UmamiMIT cookieless analytics; Cloud Hobby is a real free tier

   Free / OSS · OSS/MIT · 39.5k GitHub stars

   VerdictMIT analytics. Free forever self-host; Cloud Hobby if you want $0 managed for a single site.

   CatchNot PostHog/GA depth — no session replay/heatmaps on Hobby/self-host the way Cloud Business sells them. Self-host means you own updates, backups, and a growing DB. Vs Plausible (paid SaaS-first) and PostHog.

3. 3.OpenStatusAGPL-3.0 status/uptime as code — Terraform/CLI/MCP

   Free / OSS · Freemium · 9.2k GitHub stars

   VerdictAGPL status/uptime as code. Free Hobby is tiny; self-host or pay when monitors multiply.

   CatchAGPL-3.0 — network copyleft on modifications you ship as a service. free cloud: one monitor / one page / 10m checks — fine for a side project, not a fleet. Vs Better Stack / Checkly-class SaaS, OpenStatus wins on OSS+IaC; you trade managed depth for license+self-host ops.

4. 4.GatusApache-2.0 health checks and status page with alerts

   Free / OSS · Apache-2.0 · 12.3k GitHub stars

   VerdictThe uptime checker for teams that want status checks in git — pick it over Uptime Kuma if YAML beats clicking.

   CatchConfig is YAML-only, with no UI for adding checks, which is great for GitOps and less great for non-engineers. It checks from wherever you run it, so you need a second location if you want to catch outages of that host itself. Suites are still marked alpha. A managed Gatus.io exists if you would rather not host it.

5. 5.KenerMIT status page system built with SvelteKit

   Free / OSS · OSS/MIT · 5.2k GitHub stars

   VerdictA pretty, free public status page — the page, not your whole monitoring stack.

   CatchIts own README says it is not trying to replace Datadog or Atlassian Statuspage; checks run from your server only, so pair it with an external monitor. Smaller community than Uptime Kuma or Gatus, and the 4.x line moved fast.

6. 6.Grafana PyroscopeAGPL-3.0 continuous profiling platform

   Free / OSS · AGPL-3.0 · 11.7k GitHub stars

   VerdictThe open continuous profiler to run next to Grafana — cheap to operate since 2.0.

   CatchAGPL-3.0, like the rest of Grafana's backends, so modified hosted versions must share source. Profiling has overhead and storage cost, so sample sensibly. You get the most out of it inside the Grafana stack; standalone it is less convenient.

7. 7.HyperDXMIT logs, traces and session replay search on ClickHouse

   Free / OSS · OSS/MIT · 10k GitHub stars

   VerdictThe best open UI if your telemetry already lives in ClickHouse.

   CatchYou need ClickHouse, either self-run (ClickStack bundles it with the OTel collector) or ClickHouse Cloud, and ClickHouse is its own ops skill. Since joining ClickHouse, the direction follows ClickStack. Releases are split between app, CLI and other packages, which makes version tracking fiddly.

8. 8.CorootApache-2.0 eBPF observability with service maps

   Free / OSS · Apache-2.0 · 8k GitHub stars

   VerdictThe fastest way from zero to a useful service map on Kubernetes.

   CatcheBPF agents need privileged access and a recent Linux kernel on every node. Some features, such as AI root-cause analysis and SSO, are in Coroot Enterprise. It is opinionated about how it stores data (Prometheus plus ClickHouse), so it is another stack to run.

9. 9.OpenLLMetryApache-2.0 OpenTelemetry instrumentation for LLM apps

   Free / OSS · Apache-2.0 · 7.5k GitHub stars

   VerdictThe vendor-neutral way to get LLM calls into your existing tracing.

   CatchTraces can include prompts and completions, which may hold personal data, so configure content capture deliberately. The Traceloop SDK defaults point toward Traceloop's hosted platform; set your own exporter. It is instrumentation, not a UI, so you still need a backend.

10. 10.GreptimeDBApache-2.0 metrics, logs and traces database

    Free / OSS · Apache-2.0 · 6.7k GitHub stars

    VerdictAn interesting one-engine alternative to the Prometheus + Loki + Tempo trio.

    CatchIt is a younger system than Prometheus, Loki or ClickHouse, and the README says the core is Apache-2.0 — some enterprise and cloud features are commercial. Grafana integration works but is less native than Mimir/Loki. Plan object-storage costs and compaction.

Also reviewed (13)

• Pixie — Apache-2.0 eBPF in-cluster observability for Kubernetes
• Grafana Alloy — Apache-2.0 OpenTelemetry Collector distribution
• Grafana Mimir — AGPL-3.0 scalable long-term Prometheus storage
• Parca — Apache-2.0 eBPF continuous profiling down to the line number
• Uptrace — AGPL-3.0 OpenTelemetry APM on ClickHouse and Postgres
• Odigos — Apache-2.0 distributed tracing without code changes
• Perses — Apache-2.0 CNCF dashboards with an open dashboard spec
• Sloth — Apache-2.0 SLO generator for Prometheus rules and alerts
• VictoriaLogs — Apache-2.0 zero-config schema-free log database
• Parseable — AGPL-3.0 observability data lake in a single binary
• Nightingale — Apache-2.0 alerting hub for your existing data sources
• Alertmanager — Apache-2.0 Prometheus alert routing and silencing
• Apache HertzBeat — Apache-2.0 agentless monitoring, alerting and status pages in one