Specification for TraceContext propagation format
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SergeyKanzhelev and reyang fix example - = is not allowed as a tracestate entry value (#189)
* fix example - = is not allowed as a tracestate entry value

* two more http specifiers
Latest commit bd9944a Oct 10, 2018


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Distributed Tracing Working group

This repository is associated with the Distributed Trace Context Working Group.

Specification for distributed tracing context propagation format:

Team Communication

Overview of team related communication channels:

We appreciate feedback and contributions. Please make sure to read rationale documents when you have a question about particular decision made in specification.


This specification defines formats to pass trace context information across systems. Our goal is to share this with the community so that various tracing and diagnostics products can operate together.

Reference Implementations

TODO: add link here

Why are we doing this

  • If this becomes popular, frameworks and other services will automatically pass trace IDs through for correlated requests. This would prevent traces from hitting dead ends when a request reaches an un-instrumented service.
  • Once aligned on a header name, we can ask for a CORS exception from the W3C. This would allow browsers to attach trace IDs to requests and submit tracing data to a distributed tracing service.
  • Loggers can reliably parse trace / span IDs and include them in logs for correlation purposes.
  • Customers can use multiple tracing solutions (Zipkin + New Relic) at the same time and not have to worry about propagating two sets of context headers.
  • Frameworks can bless access to the trace context even if they prevent access to underlying request headers, making it available by default.


See Contributing.md for details.