Correlation IDs

Definition

A correlation ID is an identifier attached to records that belong to the same request, operation, or workflow.

Signals

• Logs
• Traces

Why use it

Find every record for a failed checkout across service boundaries.

Common use cases

• Investigate customer requests
• follow background jobs
• join application logs.

Benefits

• Exact joins reduce ambiguous timestamp searches.

Limitations

• IDs must be propagated consistently. A custom request ID is not automatically a trace ID. Never use per-request IDs as metric labels.

Practical pattern

Generate an ID at ingress, validate incoming values, and include it in structured logs. Keep trace_id and span_id as distinct fields.

Supported by

Documented examples, not an exhaustive compatibility list. Features require suitable instrumentation and configuration; availability can depend on the runtime, backend, and subscription.

• OpenTelemetry — Propagates trace context; applications can use the trace ID to connect records.

Related concepts

• Context Propagation
• Log Correlation
• Trace Correlation

Investigation patterns

• Trace to Logs
• User Session to Backend Trace
• Queue Producer to Consumer

Related guides

• What is Observability?
• What is MTTR?
• OpenTelemetry: Queue Context, Retries and Batches

FAQ

Is a correlation ID the same as a trace ID?

A trace ID identifies one distributed trace. A correlation ID may identify a broader business workflow spanning several traces.