Logs and live tail

Persist, query, and tail Worker logs on the selected open-compute instance.

Inspect logs through Dashboard Live Tail or the existing SDK/API queries. cf currently has no equivalent terminal streaming tail command; server logs and live tail remain available.

Configure logs

Use cf’s observability configuration. Log enablement, sampling, invocation logs, and persistence are supported. External log destinations and traces are not.

// worker.observability in cloudflare.config.ts
({
  observability: {
    enabled: true,
    headSamplingRate: 1,
    logs: { enabled: true, invocationLogs: true, persist: true },
    traces: { enabled: false },
  },
});

Persisted telemetry supports the events and invocations query views, keys and values discovery, filters, and one live-tail session scoped to a selected script. Retention, database size, invocation log size, query timeframe and event count, ingest queue capacity, tail session count, and tail client buffering are bounded by the instance configuration.

Local differences

Telemetry is stored on the selected instance rather than Cloudflare’s global analytics service. Hosted-only metadata is omitted, regex filters use a bounded RE2-compatible subset, and account-wide live tail is unavailable. Calculations, traces, agents, requests, saved queries, Tail Workers, Logpush, and external destinations are not supported.

See Behavior differences, Limits, and the Management SDK.