Health Check

With healthcheck on (the default) the build produces a second, tiny executable — build/healthcheck — and the server answers GET /_health:

{
  "status": "ok",
  "uptime": 42,
  "rss": 51249152,
  "pid": 1,
  "timestamp": "2026-09-19T10:00:00.000Z"
}

The binary requests that endpoint and exits 0 on a 200 with status: "ok", 1 otherwise. It reads the same HOST, PORT and SOCKET_PATH as the server (a wildcard HOST is probed over 127.0.0.1), so it needs no extra wiring.

Docker

HEALTHCHECK --interval=30s --timeout=5s --start-period=5s --retries=3 \
    CMD ["./build/healthcheck"]

Or in Compose:

healthcheck:
  test: ["CMD", "/app/build/healthcheck"]
  interval: 30s
  timeout: 3s
  retries: 3
  start_period: 2s

Changing the path

adapter({ healthcheck: { path: "/healthz" } });

The binary picks up the new path automatically. HEALTHCHECK_PATH overrides it at runtime, and HEALTHCHECK_TIMEOUT (ms, default 2000) bounds the request.

Disabling it

healthcheck: false skips the binary and the endpoint, freeing /_health for your own route.