The offline player is available when Serato DJ Pro hardware is not connected, and outputs through the current default audio device.
Load a track to the Offline player by dragging and dropping onto the waveform display area, the track display area, or by pressing shift + left arrow on your keyboard. If the end of the loaded track is reached, the next track in the current playlist will automatically play next.

The offline player is a useful tool for preparing crates, auditioning tracks, and adding Cue Points and Loops. You can also use the Grid Edit mode in the offline player, by clicking on EDIT GRID, once you have loaded a track. To access the track controls, simply click on 'expanded controls' button below;

You can also show 2 decks in the Offline player, which is known as Practice mode.

SEE CUE POINTS FOR MORE INFORMATION
SEE LOOPING FOR MORE INFORMATION
SEE BEATGRIDS FOR MORE INFORMATION 
SEE PRACTICE MODE FOR MORE INFORMATION