How to Get Spotify to Crossfade Between Songs Like an Actual DJ

When you listen to a live DJ, one song doesn’t stop playing and then another start after a brief pause. Instead, the tracks transition into each one another. One popular technique for doing so is called “crossfading”. The two tracks overlap for a few seconds, the volume going down for the first track as it comes up for the second.
by Harry Guinness via How-To Geek