gRPC Swagger vs grpcui

gRPC Swagger is a free, open-source debugging tool for discovering and calling gRPC methods through Swagger UI. It uses server reflection to scan a registered endpoint, identified by host and port, and then displays available services, method definitions, and parameters. Users can invoke methods with Swagger UI’s “Try it out” control, supplying request data and headers as JSON; the headers are passed to the gRPC server as metadata. Reflection must be enabled on the gRPC service, but the setup instructions say proto files and related implementations do not need modification. The project runs from a released JAR or from source and defaults to port 8080. Configuration can show registered services and expire inactive registrations after a chosen number of seconds. Documented endpoints cover registration, service listing, method calls, and Swagger documentation. It is self-hosted, available for API and web use, and licensed under MIT.

grpcui is a free, open-source command-line tool for interacting with gRPC servers through a browser-based interface. It is aimed at gRPC APIs rather than REST APIs and can discover service schemas through server reflection, .proto source files, or compiled protoset files. Its interface builds dynamic forms for protobuf messages, including well-known types, oneofs, and maps, and also accepts a complete JSON request body. grpcui supports RPC methods including streaming, then displays response headers, messages or errors, trailers, and readable HTML tables. It connects to plaintext and TLS servers, including mutual TLS with client certificates. Streaming requests have a constraint: they must be constructed all at once, so bidirectional streams cannot be handled interactively like they can with grpcurl. The project also provides Go packages for embedding a form or complete web UI in a Go HTTP server. Installation is documented through Homebrew on macOS or Linux, and through the Go install command. It is released under the MIT license.