Justin Bieber -- DUI Case on Brink Of Plea Deal

Justin Bieber is about to score a very sweet plea deal in his Miami Beach DUI case ... TMZ has learned.

Sources familiar with the case tell TMZ ... prosecutors have backed off the DUI, resisting arrest and driving without a license charges, and they are working out a deal with Bieber's lawyers for the singer to plead no contest to reckless driving. The 3 charges will be dropped.

And this is the critical part ... prosecutors have backed off their demand for random drug testing ... something Bieber's lawyers would NEVER agree to for obvious reasons.

Bieber would not be entirely out of the woods ... he would be placed on probation -- it appears for 1 year -- which means he'd have to keep his nose clean.

We're told the deal could be finalized in days.