Like many developers I am working with a dual screen setup. An external 4K display (a big “Thank you” to Casey Liss for his blog post on the topic) attached to my 2015 15” MacBook Pro.

Have 2 identical displays instead of the MacBook’s built-in display and an external one would be more comfortable during working and would make more sense from an ergonomics point of view. However, I often need to take my computer to meetings and occasionally work from home, where such identical setups would become a bit too expensive. But sometimes – not always, I am trying to schedule my tasks accordingly – an external display would be nice.

Luckily I am a heavy user of the iPad Pro 12.9”, which pushes a lot of pixels around as well. It is in use mostly for private matters, but also for annotating documents and notes, drafting ideas and creating documentation. When it is not in use for any of those things it no longer is just lying around unused but can function as a mobile external display.

The app helping me doing this is call duet. It lets you chose resolution and comes with nice additional features. It is capable of simulating the touch bar introduced in last years MacBook Pro models and creates the possibility of interacting with the macOS interface through touch. I don’t use these features, because I find them a bit unwieldy. Those interactions where never meant to be use in that way. But for just having an external display on the go, I love it for what it is.