Granc vs grpcui

Granc is a free, open-source Linux command-line tool written in Rust for dynamic gRPC calls. It sends JSON payloads without requiring service Protobuf files to be compiled into the client, translating JSON to Protobuf and back at runtime. Using a descriptor, it detects unary, server-streaming, client-streaming, and bidirectional RPCs. Schemas can come from server reflection or a local binary FileDescriptorSet file. Commands list services and describe services, messages, and enums. Granc also creates static Markdown documentation cross-linked between services and types. Requests may include custom headers such as authorization or tracing metadata, and JSON is validated before transmission. The core logic is available as a separate library crate for integration tests, proxies, and automation tools. Installation is documented with cargo install --locked granc. The project has moved to Codeberg, while its GitHub repository was archived on March 9, 2026. It is offered under Apache License 2.0 or MIT. TLS support with configurable roots and client identity is on the roadmap.

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.