Insomnia is an open-source API client that lets you test and debug GraphQL, REST, WebSockets, SSE, and gRPC endpoints across Windows, Mac, and Linux. Developers use it to design, develop, and collaborate on APIs with features like request testing, response inspection, and multiple storage options (cloud, local, or Git). It's a practical alternative to command-line tools like curl when you need a visual interface for managing complex API workflows.

856 open issues · last updated Jul 21, 2026