Hurl.it - Hurl makes HTTP requests.
Boomi - The #1 Integration Cloud - Build Integrations anytime, anywhere with no coding required using Dell Boomi's industry leading iPaaS platform.
Graphical HTTP Client - Graphical Http Client is a utility to help you test and interact with REST-based web services.
Postman - The Collaboration Platform for API Development
Cocoa Rest Client - A free open source, native Apple OS X app for testing HTTP/REST endpoints
Zapier - Connect the apps you use everyday to automate your work and be more productive. 1000+ apps and easy integrations - get started in minutes.