grpcui is a command-line tool that provides an interactive web UI for gRPC servers, functioning as a browser-based alternative to Postman for gRPC APIs.
The tool solves the problem of testing and exploring gRPC services without writing client code. It works by launching a local web server that presents a dynamic HTML form for constructing and sending requests to gRPC endpoints. The form automatically adapts to the service schema, supporting all protobuf message types including well-known types, oneofs, and maps. Schema information can come from three sources: server reflection, proto source files, or compiled protoset files containing descriptor protos.
Developers should choose grpcui if they need an interactive way to test gRPC services during development or debugging. It suits projects where team members want to explore APIs without command-line tools, and where the gRPC server either supports reflection or where proto definitions are available. The tool handles both plain-text and TLS connections, including mutual TLS with client certificates. It supports all RPC method types, though streaming methods require constructing the entire request stream upfront rather than enabling true bidirectional interaction. Beyond the command-line tool, the project provides two Go library packages for embedding the UI into custom HTTP servers: a base package with form components and JavaScript, and a standalone package offering a complete HTTP handler that can be wired directly into existing servers.
The project maintains active development with regular updates to its codebase. The tool receives ongoing refinement to its core functionality and dependencies are kept current. Development activity shows consistent attention to both the command-line interface and the library packages that enable integration into other applications.
