Honest comparison

Sentinel vs Uptime Kuma

Uptime Kuma checks that the front door answers. Sentinel watches what is happening in the rooms behind it.

Start free → Read the docs

The honest version

Uptime Kuma is free, MIT-licensed, self-hosted and genuinely good at its job. If what you need is HTTP, TCP, ping and DNS checks against a handful of endpoints, it is very hard to beat at zero euros — and it ships more notification integrations than Sentinel will have for a long time. The two are not really competitors: they watch from opposite sides of the same wall.

Side by side

No asterisks, and no rows invented to make one column look better.

Vantage point
Uptime Kuma — Outside in — HTTP, TCP, ping, DNS
Sentinel — Inside the cluster — replica state, node readiness — plus any signal you push
What it can see
Uptime Kuma — Whether the endpoint answers
Sentinel — Two of three replicas ready, a node gone NotReady, memory pressure — before the endpoint stops answering
Kubernetes
Uptime Kuma — No native integration — you check the ingress URL
Sentinel — An operator, with auto-discovery by annotation
Adding a service
Uptime Kuma — Create a monitor per endpoint, in the UI
Sentinel — Annotate the workload — the service creates itself on the first signal
Notification channels
Uptime Kuma — 90+ providers built in
Sentinel — Slack, Discord, email and generic webhooks — with retries, cooldown and a circuit breaker
Who runs it
Uptime Kuma — You host it — and you get to monitor the monitor
Sentinel — Hosted in the EU; the collection agent is open source
Cost
Uptime Kuma — Free, plus a VM and your time
Sentinel — Free tier, then 9 EUR per month

So which one should you pick?

Stay on Uptime Kuma if

  • You mostly check public endpoints and it already tells you what you need.
  • You want no vendor in the loop, whether on principle or on policy.
  • You depend on one of its more exotic notification providers.

Try Sentinel if

  • You run Kubernetes and want to know a workload is degraded before it is down.
  • You want CI jobs, cron and scripts in the same health view as your cluster.
  • You would rather not host — and separately monitor — your own monitoring.

Or run both

Running both is a reasonable setup, not a compromise. Uptime Kuma answers “can my customer reach it”, from outside your network. Sentinel answers “is it healthy in there”, and can say so before the endpoint goes dark. Anything that speaks HTTP can push into Sentinel alongside your cluster, so CI, cron and scripts land on the same timeline.

anything that speaks HTTP

curl -X POST https://app.sentinel-app.io/api/v1/signals/ \
  -H "Content-Type: application/json" \
  -H "STNL-Access-Key: $KEY_ID" \
  -H "STNL-Secret-Key: $SECRET" \
  -d '{"service": "nightly-etl", "status": 1}'

Questions people actually ask

Can Uptime Kuma monitor Kubernetes workloads?

Only indirectly, by checking a URL the workload serves. It cannot see that two of three replicas are ready, that a node is under memory pressure, or that a rollout never converged — none of that surfaces on an HTTP check until it is already too late.

Is Sentinel open source like Uptime Kuma?

The Kubernetes operator is. The backend is not — the hosted service is what funds development. If self-hosting the entire stack is a hard requirement for you, Uptime Kuma is the more honest fit.

Can I keep both?

Yes, and plenty of setups should: Kuma for external availability seen from outside, Sentinel for what is happening inside the cluster and for everything else that pushes signals.

Other comparisons

Sentinel vs Prometheus → Sentinel vs Datadog →

Simple, transparent pricing

Free to get started. Scale as you grow.

View plans →