RESTClient - RESTClient can be used to test variety of HTTP communications and RESTful webservices.
Postman - The Collaboration Platform for API Development
Insomnia REST - The most intuitive cross-platform REST API Client ð´
Requester - HTTP client plugin for Sublime Text with an expansive feature set, modern UX, elegant syntax and...
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.
Runscope - Log, monitor and measure your API usage to solve API problems fast.