Data sources and limits

VIN decode: NHTSA vPIC (factory data only; not accidents, title or condition)
Recalls: NHTSA Recalls API (per year/make/model; check a specific VIN at nhtsa.gov/recalls)
Complaints: NHTSA (unverified owner reports)
Fuel economy: fueleconomy.gov
Safety stars: NHTSA 5-Star ratings
Sales tax: Tax Foundation state + average local (estimated)
Doc-fee rules: state statutes and regulators (by state)

No market values, listings, history or reliability scores in the free tools.