Aspen

Aspen is a free native macOS app for testing REST APIs locally, with no login required. It includes an AI assistant (Alfred) that can generate integration code, data models, and OpenAPI specs to speed up development. Designed with a zero-trust policy, all data stays on the user's machine, ensuring privacy and security. The Collections feature allows organizing, importing, exporting, and sharing API requests for better collaboration. Aspen is optimized for REST APIs, providing fast, one-click testing within a super-optimized interface. It is built for developers and API designers who want a lightweight, privacy-first tool without account overhead.