With the proliferation of complex JavaScript websites and applications, we are finding that browser-side issues such as slow network calls, poor render times, and JavaScript errors can have a big impact on user experience. Server-side monitoring clearly does not help in these scenarios and often these types of issues are being missed. Front end instrumentation extends the types of monitoring we are used to with server-side code to the browser, allowing for early warning of potential issues and far easier diagnosis should production issues occur.