grpc-gateway

gRPC-Gateway is a plugin for the Google protocol buffers compiler (protoc). It reads protobuf service definitions and generates a reverse-proxy server that translates a RESTful HTTP API into gRPC, based on google.api.http annotations in the service definitions. This allows a service to be exposed in both gRPC and RESTful JSON styles at the same time. Key capabilities described in the README: - Generates JSON API handlers and a reverse proxy from proto definitions. - Supports method parameters in the request body, path, and query string. - Handles enum fields in path parameters, including repeated enum fields. - Maps streaming APIs to newline-delimited JSON. - Three mapping approaches: default HTTP mapping (with generate_unbound_methods), custom google.api.http annotations, or an external gRPC Service Configuration file (optionally with standalone=true). - Optional OpenAPI/Swagger generation via protoc-gen-openapiv2, and an alpha protoc-gen-openapiv3 for OpenAPI 3.1 output. - Installation via go install, Go 1.24 tool directives, or prebuilt release binaries with SLSA3 signatures. - Usage with buf (local or remote plugins) or protoc, with example buf.gen.yaml configurations. - A runtime library (runtime.NewServeMux) for writing the HTTP entrypoint that proxies to a gRPC server endpoint. - Documentation site, examples directory, and a GopherCon UK 2019 video intro. The README notes that protoc-gen-openapiv3 is alpha and its output shape may change, while protoc-gen-openapiv2 is the production-stable option. It also mentions path-parameter renaming for duplicate mappings and unescaping modes for URL-encoded slashes.