Mastering is final polish plus loudness that translates across every playback system. In 2026 every major platform normalises loudness, so the target is roughly -14 LUFS integrated with a true peak below -1 dBTP for a one-size-fits-most streaming master.
Chasing loudness is a lost war: master to -8 LUFS and Spotify simply turns you down about 6 dB — you lose dynamics and transients for nothing. A dynamic -14 master often sounds bigger after normalisation.
For electronic music you’ll often keep two masters: a -14 LUFS version for streaming and a louder club/DJ version. Never send the club master to streaming.