docs/source/configuration/metrics.md

Metrics

The server can expose prometheus metrics on port 5565 but is off by default. You may enable the metrics server with METRICS_ENABLED=true and change the port with METRICS_PORT=1234.

In development with npm run dev, the metrics server does not shutdown gracefully due to Sveltekit not providing hooks for restart. It's recommended to disable the metrics server in this case.