Selenium - Selenium automates browsers. That's it! What you do with that power is entirely up to you. Primarily, it is for automating web applications for testing purposes, but is certainly not limited to just that.
Loader.io - Loader.io is a simple cloud-based load testing service
DevTest - Test management solution for efficient quality assurance
LoadFocus - Cloud Testing Infrastructure | Cloud Testing Services and Tools for Websites & APIs.
Beta Testing - Beta Testing is an all-in-one feature-rich technical testing solution created to help small to large size businesses test and enhance their products through insights.
Loadium - Performance Testing & Load Testing Tool