Experimental utilities (DiagnosticServlet and DiagnosticInterceptor) for tests and diagnostics. DiagnosticServlet Experimental and simple custom servlet which enables setting component's communication id's. This will help one to write scalability tests for Vaadin with e.g JMeter or Gatling. **For VAADIN 8.1 use ConnectorIdGenerator add-on instead** See the following wiki articles for more information about the scalability testing: http://bit.do/vaadin-gatling http://bit.do/vaadin-jmeter Caution! Use unique ids for components! DiagnosticInterceptor Server-side interceptor for recording Push WebSocket communication. You can use recorded requests e.g. for scalability testing a Vaadin application with JMeter. See also (https://github.com/johannest/JMeter-WebSocketSampler) for a customized WebSocketSampler plugin for JMeter.