ReqLab
An offline, account-free desktop API client built with Kotlin and Compose Multiplatform, supporting HTTP requests, streaming, and Model Context Protocol server testing as an alternative to Postman or Insomnia.
ReqLab is a desktop-first API client for macOS, Linux, and Windows built with Kotlin and Compose Multiplatform, designed to run entirely offline with no account requirement or telemetry. It supports the standard HTTP methods, live query-parameter editing, multiple request body types including JSON, GraphQL, and form data, several authentication schemes, retry controls, and copying a request as curl.
It also handles streaming responses such as server-sent events and NDJSON on a single request, and brings Model Context Protocol server testing into the same workspace as HTTP requests, letting a user configure an MCP server once and reuse its environments, variables, and authentication alongside REST collections. Sample fixtures demonstrate an OpenAI-compatible chat completion stream, an SSE endpoint, and an MCP connection.