Postman - The Collaboration Platform for API Development
devZing - Bugzilla, MantisBT and Subversion Hosting Software Development - Simplified
Assertible - Assertible software provides you with a simple and quick way to monitor your web services. It comes with automated QA tools that users can utilize to test and monitor their web services on different platforms and environments.
GoReplay - GoReplay is an open-source tool for capturing and replaying live HTTP traffic into a test environment.
API Fortress - API performance, accuracy, and uptime testing. Without code.
Testlio - Testlio is a community of expert testers that help companies release their apps with highest confidence