Observability Practical By Samson Tanimawo, PhD Published Apr 24, 2026 4 min read

Span Links: Connecting Async Flows

When a request triggers async work, span links connect the flows. The pattern, the tooling, and the visualisations.

When you need it

Producer-consumer queues. The producer's request is one trace; the consumer's processing is another. Without a link, you cannot follow the flow.

Batch jobs that process events from many requests. The job's trace links to all the requests.

OTel's Span#addLink() API. Pass the trace ID and span ID of the originating work.

Most queue libraries auto-instrument. Verify; some do not.

Vendor support varies. Honeycomb, Datadog, Tempo all show span links to varying degrees.

Test before relying. Some vendors store the link but do not visualise it.