How would you implement a Distributed Tracing system in a Node.js Microservices architecture?

Use OpenTelemetry with AsyncLocalStorage to propagate trace contexts across asynchronous boundaries and network hops.

Distributed tracing requires a Trace ID that follows a request across services. In Node.js, passing this manually through every function is brittle. Instead, we use AsyncLocalStorage (from the async_hooks module) to store the context. OpenTelemetry (OTel) instrumentation hooks into HTTP and database modules to automatically inject headers (like B3 or W3C Trace Context) into outgoing requests and extract them in downstream services.