Sentry.io - From error tracking to performance monitoring, developers can see what actually matters, solve quicker, and learn continuously about their applications - from the frontend to the backend.

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.

AppSignal - We monitor the software that makes your customers happy.

DalekJS - DalekJS is an open source UI testing tool.

BugSnag - Not all bugs are worth fixing. Prioritize and fix software bugs that matter while improving software stability with every release.

Webinject - WebInject is a free tool for automated testing of web applications and web services.