RESTClient - RESTClient can be used to test variety of HTTP communications and RESTful webservices.
Graphical HTTP Client - Graphical Http Client is a utility to help you test and interact with REST-based web services.
SoapSonar - Crosscheck Networks designed SOAPSonar from the ground-up as a comprehensive testing solution with...
Hurl.it - Hurl makes HTTP requests.
Insomnia REST - The most intuitive cross-platform REST API Client ð´
soapUI - SoapUI Pro is one of the most prominent API testing platforms around, allowing developers to quickly prototype the functions of their apps and get them to market with little hassle.