Crossfade is a feature on Spotify that allows you to play tracks back to back without any silence between them, creating a DJ-like experience by overlapping songs so theres no dead air. When crossfade is enabled, the end of one song will fade out as the next song starts to fade in. You can enable crossfade on both the desktop and mobile versions of Spotify. To enable crossfade on the desktop app, you need to click on the down arrow next to your account name, choose Settings, scroll down to the Playback section, and click the switch next to Crossfade songs. You can then adjust the slider to set the length of the crossfade, which can be anywhere between 0 and 12 seconds. On the mobile app, you can find the crossfade slider in the settings menu. Note that crossfade cannot be set when using Spotify Connect.