Techniques for monitoring web application performance are provided. A request for a web application is received at an application server. A response pipeline at the application server generates client application code corresponding to the requested web application. The client application code is intercepted in the response pipeline. Instrumentation code is inserted into the intercepted client application code to generate an instrumented client application code. The instrumentation code is configured to be executed when the instrumented client application code is rendered at the client to capture performance information at the client, and is configured to transmit the captured performance information from the client.