Postman

Postman makes developing APIs easy and it is the most complete toolset for API development. Postman has been designed with developers in mind and it is packed with lots of options and features:

• It is the most widely used REST client around the world
• It has been designed to support API developers from the ground up
• It has an intuitive user interface to create workflows, add tests, send requests to endpoints, and save the responses for the API calls 

Postman's options and features are:

• It stores all the requests made
• It supports variable substitutions  
• It has support for creating environments
• It has support for tests & pre-request scripts
• It has support for collections
• It supports request descriptions