The Voice Diagnostics Web App is a new tool designed to simplify checking for browser calling readiness and diagnosing network related issues in VoIP services, particularly those using Twilio Programmable Voice. The app is an open-source ReactJS application that tests browser compatibility as well as network bandwidth and connectivity, providing detailed results and warnings to help identify underlying issues. It includes features such as support for testing multiple edge locations, tabulation of results, detection of TURN requirements, and easy sharing of JSON formatted test reports. The Voice Diagnostics Web App is available in beta and can be deployed using Twilio's serverless platform. Additionally, the RTC Diagnostics SDK provides classes to test bitrate, microphone, and speakers, as well as a new function called `Device.testPreflight` that places a loopback call to analyze network connectivity and audio quality.