I heard lots about the app called Sketch, citing it the “industry standard” for designing UI in mobile apps. Luckily I found that it has a trial version, so I began learning to use it. It certainly didn’t disappoint me. Its snap and alignment features are very handy and simple to use. The design interface is simple, and as someone who loves shortcut keys, Sketch offers a separate hotkey for each of the most frequently used tools such as rectangle (R), line (L) and text (T). After a UI has been designed, it can be immediately imported into Xcode for further development. Pretty cool!