REST Assured is a Java library that provides a domain-specific language (DSL) for writing powerful, maintainable tests for RESTful APIs.
It is developed by JayWay Company and it is a really powerful catalyzer for automated testing of REST-services. REST-assured provides a lot of nice features, such as DSL-like syntax, XPath-Validation, Specification Reuse, easy file uploads and with those features we will handle automated API testing much easier.
REST-assured was designed to simplify the testing and validation of REST APIs and is highly influenced by testing techniques used in dynamic languages such as Ruby and Groovy. Rest Assured has a gherkin type syntax.