Metric Registry https://metric-registry.base14.io/ is a growing searchable catalog of observability metrics extracted directly from source repositories across the OpenTelemetry, Prometheus, and Kubernetes ecosystems. It scans code, documents and websites to gather this data.

If you've ever tried to answer "what metrics does my stack actually emit?", you know the pain. Observability metrics are scattered across hundreds of repositories, exporters, and instrumentation libraries. The OpenTelemetry Collector Contrib repo alone has over 100 receivers, each emitting dozens of metrics. Add Prometheus exporters for PostgreSQL, Redis, MySQL, Kafka. Then Kubernetes metrics from kube-state-metrics and cAdvisor. Then your application instrumentation across Go, Java, Python, and JavaScript.

Each source uses different formats:

    OpenTelemetry Collector uses metadata.yaml files

    Prometheus exporters define metrics in Go code via prometheus.NewDesc()

    Python instrumentation uses decorators and meter APIs

    Some sources just have documentation (if you're lucky)

You can see the details of how the registry was built on the repo - https://github.com/base-14/metric-library . the current setup scans through many sources and has details for 3700+ metrics. The scan runs every night(/day depending on where you live)