open-telemetry/opentelemetry-proto

OpenTelemetry Proto is a Protocol Buffer definitions repository that specifies the OTLP (OpenTelemetry Protocol) and related protocols for telemetry data exchange.

The repository solves the problem of standardizing how observability data—traces, metrics, logs, and profiles—is serialized and transmitted between systems. OTLP provides the primary data delivery mechanism for OpenTelemetry, supporting both gRPC and HTTP transport. The tool also defines Process Context Sharing, a separate protocol for sharing process-level resource attributes via memory-mapped regions with external tools like profilers, without requiring gRPC or HTTP. By publishing Protocol Buffer definitions, the repository enables language-independent implementations across the OpenTelemetry ecosystem.

Developers should adopt this repository if they are building OpenTelemetry language libraries, exporters, collectors, or other components that need to serialize and exchange telemetry data. The tool suits projects that require standardized, interoperable telemetry protocols. Most OTLP components—including traces, metrics, logs, and their collectors—are marked stable in both binary Protobuf and JSON wire formats. Profiles and Process Context Sharing remain in development maturity. The repository provides build targets to generate gRPC client libraries for multiple languages including C++, C#, Go, Java, Objective-C, PHP, Python, and Ruby. Language-specific OpenTelemetry libraries may publish their own generated bindings, so developers should check their language library's documentation for pre-built options.

The project maintains active contribution guidelines and accepts changes through a documented process. Development activity centers on evolving protocol specifications and maintaining Protobuf definitions as the OpenTelemetry standard matures, with particular focus on stabilizing the profiles protocol and Process Context Sharing protocol.