OpenCensus is being archived! Read the blog post to learn more Navigation : Introduction Quickstart Tracing - Span -- Name -- SpanID -- TraceID -- ParentSpanID -- StartTime/EndTime -- Status -- Time events -- Link -- SpanKind -- TraceOptions -- Tracestate - Sampling Tags Stats/Metrics Exporters zPages Service Advanced Concepts Guides Language Support Integrations FAQ Feature Matrix Code of Conduct Community Blogs Articles Codelabs TraceOptions TraceOptions TraceOptions is a byte on each OpenCensus span. Currently its last bit is set iff the span is sampled otherwise it is clear. Perhaps this table might help clarify better State in hex State in binary Meaning 0x00 00000000 Span IS NOT sampled 0x01 00000001 Span IS sampled References Resource URL TraceOptions in the OpenCensus specs https://github.com/census-instrumentation/opencensus-specs/blob/master/trace/Span.md#traceoptions SpanKind Tracestate