RPCinterfaces

RPC interfaces define the surface of a remote service as seen by clients. They specify the available operations (methods), their input parameters, return values, and possible errors. The interface acts as a contract between client and server and is typically expressed in an interface description language (IDL). Tools generate client stubs and server skeletons from the interface definition, enabling code in multiple programming languages to interoperate.

Common RPC systems use different IDLs and protocols. Protocol Buffers with gRPC use .proto files to define services and messages; Apache Thrift and Apache Avro provide their own IDLs; JSON-RPC and XML-RPC are lighter-weight, text-based protocols defined over HTTP. Interfaces typically specify method names, parameters, and return types, and may also declare metadata such as authentication requirements, timeouts, and error codes.

Key design concerns include data serialization, transport, and compatibility. Serialization converts in-memory values to a wire format, while transport defines how messages are delivered. Versioning and backward compatibility are important to avoid breaking changes. Security considerations include authentication, encryption, and integrity.

RPC interfaces support synchronous and asynchronous patterns, streaming, and bidirectional streaming in some frameworks. They are widely used in microservices, distributed systems, and cross-language integrations. When designing RPC interfaces, practitioners consider idempotency, retry strategies, and clear error semantics.