I see people that buy at auction lots and some private party buyers, will just scan the barcode on the door and itll bring up the history and what the cars are selling for currently.

What app is this?

You're likely talking about apps like VIN Scanner FastBook, VIN Scanner by Laser Appraiser, VIN Info, or autoniq VIN Scanner. These apps are super handy for anyone in the auto industry or even private buyers. They let you use your phone to scan a vehicle's VIN right off the barcode or QR code, usually found on the door or dashboard. Once scanned, they pull up all sorts of useful info, like the car's history, any accidents it's been in, its current market value, and more. Some are more geared towards dealers, offering detailed valuation and history reports from places like Carfax or AutoCheck, but there are options out there for individuals too.

Carfax.

thanks!