kong/insomnia

Insomnia is an open-source desktop application for interacting with APIs during development. If you are building or testing a web service and need to send HTTP requests, inspect the responses, and organize your request collections, Insomnia provides a graphical interface for doing that across a wide range of protocols including REST (standard HTTP APIs), GraphQL (a query language for APIs), WebSockets (persistent bidirectional connections), Server-Sent Events, and gRPC (Google's remote procedure call framework). Beyond just sending requests and seeing responses, Insomnia also lets you design APIs using a built-in OpenAPI editor with a visual preview, write and run automated test suites against your API, create mock servers to simulate an API before building the real one, and build CI/CD pipeline integrations using a command-line tool called Inso. For managing how you store your work, Insomnia offers three options: Local Vault for keeping everything on your device, Git Sync for storing collections in any Git repository without cloud involvement, and Cloud Sync for team collaboration with optional end-to-end encryption. You would use Insomnia when developing a web application or service and need to explore and test API endpoints interactively. It fills the same niche as tools like Postman. The basic functionality works without an account via a local Scratch Pad mode, while more advanced features like unlimited collaboration and Git Sync require a (free or paid) account. The application is built with TypeScript and Electron, a framework that packages web technologies into a desktop app, and runs on macOS, Windows, and Linux.