This summary highlights the key points of building a web application that enables users to engage in video chat and send messages using OpenTok for video conferencing and Nexmo In-App Messaging. The application structure includes a server-side component built with Express.js, which generates credentials for both OpenTok and Nexmo, allowing clients to connect to these services. The client-side code utilizes the `@opentok/client` library for OpenTok and `nexmo-stitch` for Nexmo, enabling features like video chat, message sending, and conversation history display. The application's frontend is built using EJS templates, which render the necessary HTML elements with the generated credentials. The final step involves running the server with npm start, allowing users to interact with the web application through a user-friendly interface.