Insomnium

Insomnium is an open‑source API client that runs entirely on the local machine, allowing developers to test GraphQL, REST, WebSockets, server‑sent events, and gRPC without any cloud services or telemetry. It stores all data locally, eliminating the need for user accounts, analytics, or external communication, and can operate offline. The client is packaged for macOS, Windows, and various Linux distributions, with pre‑built releases and an AUR package for Arch Linux, and it can also be built from source using Node.js.

The tool targets developers who need a privacy‑focused environment for API experimentation and debugging, especially those who prefer to avoid mandatory online accounts. By for a fork of the Insomnia codebase prior to the introduction of compulsory login, Insomnium retains familiar UI and workflow while removing tracking components. It supports importing existing Insomnia configurations, facilitating migration for current users.

Although the repository is no longer actively maintained, the project remains stable and functional. Contributions can continue through forking, and the codebase includes standard development scripts for linting, type checking, testing, and live‑reload execution on macOS, Windows, and Linux.