# Semantic conventions for RPC

LLMS index: [llms.txt](/llms.txt)

---

**Status**: [Release Candidate][DocumentStatus], unless otherwise specified

This document defines semantic conventions for remote procedure calls (RPC)
, also called "remote method invocations" (RMI).

> [!IMPORTANT]
> Existing RPC instrumentations that are using
> [v1.37.0 of this document](https://github.com/open-telemetry/semantic-conventions/blob/v1.37.0/docs/rpc/README.md)
> (or prior):
>
> * SHOULD NOT change the version of the RPC conventions that they emit by
>   default in their existing major version. Conventions include (but are not
>   limited to) attributes, metric and span names, and unit of measure.
> * SHOULD introduce an environment variable `OTEL_SEMCONV_STABILITY_OPT_IN`
>   in their existing major version as a comma-separated list of category-specific values
>   (e.g., http, databases, rpc). The list of values includes:
>   * `rpc` - emit the stable RPC conventions, and stop emitting
>     the experimental RPC conventions that the instrumentation emitted
>     previously.
>   * `rpc/dup` - emit both the experimental and stable RPC conventions,
>     allowing for a phased rollout of the stable semantic conventions.
>   * The default behavior (in the absence of one of these values) is to continue
>     emitting whatever version of the old experimental RPC conventions
>     the instrumentation was emitting previously.
>   * Note: `rpc/dup` has higher precedence than `rpc` in case both values are present
> * SHOULD maintain (security patching at a minimum) their existing major version
>   for at least six months after it starts emitting both sets of conventions.
> * MAY drop the environment variable in their next major version and emit only
>   the stable RPC conventions.

Semantic conventions for RPC are defined for the following signals:

* [RPC Spans](rpc-spans.md): Semantic Conventions for RPC client and server *spans*.
* [RPC Metrics](rpc-metrics.md): Semantic Conventions for RPC *metrics*.
* [RPC Exceptions](rpc-exceptions.md): Semantic Conventions for RPC client and server *exceptions*.

Technology specific semantic conventions are defined for the following RPC systems:

* [Connect](connect-rpc.md): Semantic Conventions for *Connect RPC*.
* [Dubbo](dubbo.md): Semantic Conventions for *Apache Dubbo*.
* [gRPC](grpc.md): Semantic Conventions for *gRPC*.
* [JSON-RPC](json-rpc.md): Semantic Conventions for *JSON-RPC*.

For help migrating from non-stable to stable conventions, see [the migration guide](../non-normative/rpc-migration.md).

[DocumentStatus]: /docs/specs/otel/document-status

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Section pages:

- [Semantic conventions for Connect RPC](/docs/specs/semconv/rpc/connect-rpc/)
- [Semantic conventions for Apache Dubbo](/docs/specs/semconv/rpc/dubbo/)
- [Semantic conventions for RPC exceptions](/docs/specs/semconv/rpc/rpc-exceptions/)
- [Semantic conventions for gRPC](/docs/specs/semconv/rpc/grpc/)
- [Semantic conventions for JSON-RPC](/docs/specs/semconv/rpc/json-rpc/)
- [Semantic conventions for RPC metrics](/docs/specs/semconv/rpc/rpc-metrics/)
- [Semantic conventions for RPC spans](/docs/specs/semconv/rpc/rpc-spans/)