OpenAPI Editor and Visualizer is described as 'Free browser-based OpenAPI editor from Postman. Design or import a Swagger 2.0, OpenAPI 3.0, or OpenAPI 3.1 spec (YAML or JSON) and see live documentation with inline validation as you type. No signup, no install. Part of Postman's suite of free developer tools at postman' and is an website in the development category. There are more than 10 alternatives to OpenAPI Editor and Visualizer, not only websites but also apps for a variety of platforms, including Mac, Windows, Linux and Self-Hosted apps. The best OpenAPI Editor and Visualizer alternative is Insomnia REST Client, which is both free and Open Source. Other great sites and apps similar to OpenAPI Editor and Visualizer are swagger.io, Slate API Docs Generator, Stoplight and Apidog.