A framework for describing, documenting, and consuming JSON webservices

Swagger is a specification and open-source framework for describing, producing, consuming, and visualizing RESTful web services with JSON. I created Swagger while building wordnik.com. Our team needed a tool to help make our APIs easier to document, understand, and use. In the four years since its creation, a large and active community has developed around Swagger, and people are continuing to find new and interesting ways to incorporate it into their JSON webservice implementations.

Swagger's API Sandbox, circa 2011

In 2015, Amazon Web Services introduced the Amazon API Gateway with built-in support for Swagger APIs.

Swagger is also supported by Runscope.

Why WADL when you can Swagger?