DJAY PRO IS an extraordinarily useful app for DJs at every level, from high school prom to superstar. It enables you to connect hardware controllers for onstage mixing and scratching, it works with 4K video as well as music, and it uses artificial intelligence to take a lot of the guesswork out of mixing. For example, if you wish, it can automatically detect the beats and tempo of a track and sync it with another so they play in perfect time, or you can use its Automix feature to do the DJing for you if you’d rather be socializing than spinning up records. It’s also packed with power features that can completely transform tracks in real time.