Writing your application is one thing. Making the application to perform well is another. We usually forget there is somebody else on the other side of the screen, that becomes very frustrated and upset when he needs to wait until this one page finally loads. It requires a lot of experience to predict specific behaviour and to know what kind of things to avoid. And even with that there is so many different factors that can affect the end user experience. During this talk I will talk about tools and techniques you can use to measure and monitor your application performance.