Observability tracing records the path of a request as it flows through distributed services. Trace spans capture the start time, duration, and metadata for each operation in a request lifecycle. Distributed traces correlate spans across service boundaries using a shared trace identifier. OpenTelemetry provides a vendor-neutral API and SDK for instrumentation. Sampling strategies reduce storage costs by recording only a fraction of traces without losing visibility into errors. Trace visualization tools display the critical path and highlight bottlenecks in service dependencies.
