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Language Independent Interface Types For OpenTelemetry

Build Check

The proto files can be consumed as GIT submodules or copied and built directly in the consumer project.

The compiled files are published to central repositories (Maven, ...) from OpenTelemetry client libraries.

See contribution guidelines if you would like to make any changes.


See additional requirements for OTLP/JSON wire representation here.

Generate gRPC Client Libraries

To generate the raw gRPC client libraries, use make gen-${LANGUAGE}. Currently supported languages are:

  • cpp
  • csharp
  • go
  • java
  • objc
  • openapi (swagger)
  • php
  • python
  • ruby

Maturity Level

Component Maturity
Binary Protobuf Encoding
common/* Stable
resource/* Stable
trace/trace_config.proto Alpha
JSON encoding
All messages Stable

(See maturity-matrix.yaml for definition of maturity levels).

Stability Definition

Components marked Stable provide the following guarantees:

  • Field types, numbers and names will not change.
  • Numbers assigned to enum choices will not change.
  • Service names and service package names will not change.
  • Service operation names, parameter and return types will not change.

The following changes are allowed:

  • Message names may change.
  • Enum names may change.
  • Enum choice names may change. This is allowed because enum choice names are not sent on the wire.
  • The location of messages and enums, i.e. whether they are declared at the top lexical scope or nested inside another message may change.
  • Package names may change.
  • Directory structure, location and the name of the files may change.

Note that none of the above allowed changes affects the binary wire representation or the JSON wire representation.

No guarantees are provided whatsoever about the stability of the code that is generated from the .proto files by any particular code generator.


In some cases we are trying to experiment with different features. In this case, we recommend using an "experimental" sub-directory instead of adding them to any protocol version. These protocols should not be used, except for development/testing purposes.

Another review must be conducted for experimental protocols to join the main project.