Jest is a delightful JavaScript Testing Framework with a focus on simplicity.

Swagger UI allows anyone — be it your development team or your end consumers — to visualize and interact with the API’s resources without having any of the implementation logic in place

Fully integrated API and web service testing capabilities that automate end-to-end functional API testing.

Design, debug, and test APIs locally or in the cloud

Postman is an API platform for building and using APIs. Postman simplifies each step of the API lifecycle and streamlines collaboration so you can create better APIs—faster.

Testing and validating REST services in Java is harder than in dynamic languages such as Ruby and Groovy. REST Assured brings the simplicity of using these languages into the Java domain.