Grafana dashboard for Air Pipe managed hosted metrics: requests, failures and latency per config and interface, and series against your plan's limit. With a three-route demo API to fill it, and the scrape config for your own Prometheus.
Deploy this config and three things appear immediately with zero extra work; Prometheus Metrics, Open Telemetry Tracing, OpenAPI Spec documentation. Every request becomes a trace you can inspect end-to-end: method, route, status code, latency, and which actions ran inside it. No annotations beyond the config. No code. No separate instrumentation setup.