grpcmock-go vs grpcui

grpcmock-go is a free, MIT-licensed Go module providing gRPC testing utilities. It helps tests mock gRPC servers, configure expectations for methods, headers, and payloads, and invoke client calls. Supported methods include unary, client-streaming, server-streaming, and bidirectional-streaming patterns. Request matching can use exact values, regular expressions, JSON, or custom matchers. Mock responses may return payloads, errors, or custom-handler results, and streaming client invocations can use custom handlers. Services can be registered from generated Go code, service instances, or individual methods when generated code is unavailable. The project recommends MockServerWithBufConn for in-memory application testing, with examples using bufconn listeners and context dialers. Installation uses `go get go.nhat.io/grpcmock`, and Go 1.25 or later is required. GitHub lists v0.34.0, released December 12, 2025, as the latest release. The Open-source Go module plan costs nothing.

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.