The new Video Diagnostics Web App is an open source ReactJS application that tests participants' device and software setup, connectivity with the Twilio Cloud, and network performance to help identify issues with high-quality video calls. The app provides stepwise tests, a recommended course of action when tests fail, and an approachable UX for non-technical end users with access to network-related statistics. It is built using Twilio's RTC Diagnostics SDK and JS Video SDK, easily customizable, free to deploy and use, and can be deployed in minutes. The app generates a JSON report that includes test results and device/network information, allowing users to share it with support teams or administrators for further analysis.