If you have created a REST API through the learning path, then you should try implementing REST in a real project. Do you have a specific service you are hoping to use? I strongly recommend you put your learning into practice and build a Mendix app with REST! If you have a use case, build one that both consumes and publishes REST services and don't forget to include Error Handling. Read up on Mendix and Swagger as well to make sure you understand the published REST documentation. Lots of people use Postman to test the APIs so that is a good tool to get familiar with.