Insomnia is a powerful REST API client with cookie management, environment variables, code generation, and authentication for Mac, Window, and Linux. It's designed to help developers build and test APIs efficiently with a clean, intuitive interface.
Swagger is a suite of tools for API developers that includes OpenAPI Specification (formerly Swagger Specification), Swagger UI for interactive documentation, and various tools for API design, building, and testing. It's the most popular framework for designing and documenting REST APIs.