Building a video chat app with ASP.NET Core 2.2, Angular, and Twilio requires setting up a server-side application that uses ASP.NET Core to serve the Angular single-page application (SPA) and handle real-time user interactions. The client-side application uses the Twilio JavaScript SDK to establish video connections and communicate with the server. The application includes features such as room creation, participant joining, and video streaming, all while providing a seamless user experience. By leveraging ASP.NET Core's dependency injection and Angular's observables, developers can build a scalable and maintainable video chat app that integrates with Twilio's Programmable Video service.