Do I need to register my DJI Mavic Mini Drone?
The Mavic Mini weighs only 249 grams
According to the FAA if the drone is under 250 grams you do not need to register it for recreational use. Keep in mind too, that if you add anything to the drone this may take if over the 250 gram weight.

If you use the drone commercially, then you need to register the drone with the FAA.