Cloudflare Worker Telemetry

Implementation evidence

Cloudflare Worker Telemetry: from boundary to verified row

Use Cloudflare Worker Telemetry at a controlled application boundary, keep the event contract small, and verify a known outcome before building aggregate views.

1
Choose the outcome
Edge API monitoring
2
Define the contract
worker_name, route_template, method, status_code, colo, and trigger_type
3
Instrument the boundary
Use ctx.waitUntil only for a delivery promise whose failure is observed; otherwise a Worker can return before telemetry is flushed.
4
Verify the evidence
Exercise a known fixture, then inspect edge_request_completed for one correctly typed terminal row.

Before you start

Prerequisites and boundaries

A Worker secret binding for the Telemetry API key
ExecutionContext available for explicitly managed background delivery
Normalized route names and an allowlist for Cloudflare request metadata

Delivery setup

Install and initialize server-side

Import telemetry-sh in server-only code and initialize it once with process.env.TELEMETRY_API_KEY. Keep ingestion credentials out of browser bundles, client-visible environment variables, source control, logs, and exception messages.

cloudflare-workers-install

npm installation

bash

npm install telemetry-sh

1Prepare one reusable server-side delivery client with bounded network behavior.
2Add the outcome event at the success, failure, retry, or timeout boundary.
3Send controlled fixtures and inspect the stored rows before enabling an alert.

Snippet

Start with one structured event

Add this shape where the workflow completes, fails, or retries. Then build the dashboard from real fields.

cloudflare-workers

Cloudflare Worker Telemetry event

javascript

await telemetry.log("edge_request_completed", {
  worker_name: "events-api",
  route_template: "/api/events",
  method: "POST",
  status_code: 202,
  colo: request.cf?.colo,
  latency_ms: 42,
  status: "success",
  release: env.APP_RELEASE,
});

Event contract

worker_name, route_template, method, status_code, colo, and trigger_type

status, latency_ms, cpu_time_ms when available, and error_type

request_id, queue_name, attempt, release, and environment

Implementation checkpoints

Checkpoint 1

Use ctx.waitUntil only for a delivery promise whose failure is observed; otherwise a Worker can return before telemetry is flushed.

Checkpoint 2

Record route templates rather than raw URLs, and do not log cookies, authorization headers, request bodies, client IP addresses, or unrestricted cf properties.

Checkpoint 3

Keep Workers Logs for runtime diagnostics and emit compact Telemetry events for reviewed application outcomes instead of duplicating every console record.

Verification

Prove the event arrived

Run this after exercising known success and failure cases. Replace the fallback table name if your final event contract differs from the snippet.

cloudflare-workers-verification

Cloudflare Worker Telemetry verification query

sql

SELECT *
FROM edge_request_completed
ORDER BY timestamp_utc DESC
LIMIT 20;

Confirm one terminal row per logical outcome, with the expected status, identifiers, units, and UTC time.

Inspect the inferred schema and verify that retries do not change field types or generate a new logical event ID.

Search the stored fields for credentials, raw payloads, prompts, private content, and unbounded error messages.

Exercise a provider timeout, ingestion rejection, and process shutdown before treating the dashboard as complete.

Implementation references

Review the event contract, data-safety guidance, and upstream primary documentation before enabling a new production path.

API reliability use case Correlation IDs API reliability by release Cloudflare Workers observability Cloudflare Worker secrets

Production boundary

Keep the outcome event small and recoverable

This pattern provides

A bounded, SQL-ready outcome beside the upstream workflow.
Stable fields for dashboards, alerts, and cross-event correlation.
A fixture-driven path for validating success, failure, retry, and timeout behavior.

This pattern does not provide

An OTLP exporter, automatic collection pipeline, or replacement for detailed traces and diagnostic logs.
Exactly-once delivery merely because the payload contains an event ID.
Permission to collect raw provider payloads, user content, credentials, or regulated data.

Delivery and idempotency Batching and shutdown Troubleshoot ingestion

Event schema starting points

Review the row grain, emit boundary, required types, privacy classes, example payload, and validation checklist before adapting a query or snippet to production.

API reliability10 fields