Many of us will find new gadgets under the tree this Christmas. This means that apps, too, need to keep up to ensure a smooth user experience across the growing range of devices.

Creating a seamless cross-device user experience is vital for any app. But what is it really all about?

For some of us, a few new gadgets might account for some of the presents appearing under the Christmas tree. When the lucky ones unwrap their new mobile device, they'll have around 1.5 million apps to browse through on its online store, apps that can be used on phones, tablets, laptops, desktops, and – quite literally – everything in between. Phablets, laptop-tablet hybrids and touch-screen desktops have blurred the lines of device categorisation. While the wide range of devices just keeps getting wider, apps need to keep up the pace - not only do they need to be compatible with any device type, but actively utilise multiple devices to enhance the experience the app can offer.

When we use an app, we get to know it. We get a feel for the layout, the location of elements and features become a part of our memory. Cross-device experience is about honouring the users’ rapport with an app, while adapting for its intended platform. Familiar, yet fluid. So, what are the golden rules? Luke Wroblewski, a Product Director at Google with an impressive track record of interface design, outlines four key points to consider. Firstly, Access. Quite simply, an app should offer the same features on whichever device is used to access it. These features should, however, be optimised for the device. A basic example would be using larger icons on a mobile app, so that it is better suited for a touch screen.

When hopping between devices, users want to be able to “pick up where they left off”, which brings us to point number two: Flow. This requires real-time sync as opposed to users actively having to save any changes, so that whatever you’ve done on the desktop app are ready and waiting for you on your tablet – and vice versa.