Postman is a software which you can use to test REST APIs. Postman has an easy to use graphical user interface. It also has many helpful features to help you with testing your REST API. Postman is available for Windows, Mac and Linux. Postman is also available as a Chrome plugin. So, you can use Postman inside your Google Chrome browser. Postman has a free version and paid versions. You can do almost everything with the free version. I will use the free version in this article.