Swagger offers a specification and a complete framework implementation for describing, producing, consuming, and visualizing RESTful web services. The Swagger framework works with many popular programming languages, such as Java, Scala, Clojure, Groovy, JavaScript, and .NET.

Swagger was initially developed by Wordnik (a property of Reverb) for meeting their in-house requirements, and the first version was released in 2011. The current release is Swagger 3.0. The Open API specification and public tools are open source, supported by many vendors, such as PayPal, Apigee, and 3scale.

The Swagger framework has the following three major components:

• Server: This component hosts the RESTful web API descriptions for the services that the clients want to use
• Client: This component uses the RESTful web API descriptions from the server to provide an automated interfacing mechanism to invoke the REST APIs
• User interface: This part of the framework reads a description of the APIs from the server, renders it as a web page, and provides an interactive sandbox to test the APIs