Did you know that you can emulate Excel formulas in ExtJS grids? Or that you can create interactive D3 visualisations from large amounts of ExtJS store data in realtime? All this and more is possible by using the power of ExtJS 5 ViewModels. The new kid on the block, ExtJS 5, has offered a host of new possibilities. The new MVVM architecture is extremely powerful but can be intimidating at first, especially when coming from MVC. Once you have flipped the switch however you will wonder how you ever managed to live without it. We will show you some examples of what can be accomplished when you really start thinking out of the box, and you can do it too. ViewModels are even more powerful than most people realise, especially when combined with things like HTML5 Canvas, WebGL, Bower components and more.