In our customer service example, the frontend application used a JavaScript structural framework (AngularJS) to test our application. Now, we will consider a different use case: a new external service is going to connect to our application using a different protocol stack. Besides JAX-RS endpoints, Quarkus has native support for the WebSocket technology that runs in the embedded Undertow web server. Therefore, in this example, we will add a WebSocket endpoint to our existing application. This will be paired with another WebSocket running in a different application.