> ## Documentation Index
> Fetch the complete documentation index at: https://healthzkit.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Scheduling

> Use Healthzkit scheduling to run slow dependency checks on an interval, serve probes from cache with low latency, and manage lifecycle with start, stop, and timestamps.

For expensive checks (database, external APIs), run them on a timer and serve probes from cache.

<Note>
  Skip `kit.start()` on serverless platforms. Run checks on demand there, and use scheduling only in
  long-lived processes.
</Note>

```ts theme={null}
const kit = createHealthKit({
  checks: [
    {
      name: "db",
      type: ["readiness"],
      adapter: { check: async () => ({ status: "ok" }) },
      schedule: { intervalMs: 30_000 },
    },
  ],
});

kit.start(); // starts background intervals for checks that define schedule
// ... on shutdown:
kit.stop();
```

## Behavior

* **`start()`** is idempotent; a second call does nothing.
* **`stop()`** clears intervals and the cache.
* When a cached result is used, that check’s **`latency`** is **0** and **`cachedAt`** is an ISO timestamp on the check result.

Scheduled runs call **`adapter.check()`** directly (there is no per-request timeout wrapper in the scheduler). Timeouts still apply when there is **no** cache entry and the probe runs the check on demand.

Timers use `unref` when available so they do not keep the process alive by themselves.