Postman is a rest client that started off as a Chrome browser plugin but recently came out with native versions for both Mac and Windows.
Can be used for both automated and exploratory testing
Can be run on Mac, Windows, Linux &Chrome Apps
Has a bunch of integrations like support for Swagger & RAML formats
Has Run, Test, Document and Monitoring Features
Doesn’t require learning a new language
SoapUI is a headless functional testing tool from SmartBear software. It comes in two flavors: Free open source version and Pro Version.
Can easily create custom code using Groovy
Drag and Drop Test Creating
Can create complex scenarios
SoapUI’s Mock Service lets you mimic web services before they are implemented
Rest-Assured is an open-source Java Domain-specific language (DSL) that makes testing REST service simple. It simplifies things by eliminating the need to use boiler-plate code to test and validate complex responses. It also supports XML and JSON Request/Responses.
Removes need to create boilerplate code required to interact with a rest service
Support BDD Given/When/Then syntax
Integrated seamlessly with Java projects