Decode VINs with the NHTSA vPIC API

Steps

1. Send a GET request to https://vpic.nhtsa.dot.gov/api/vehicles/decodevin/{VIN}?format=json, replacing {VIN} with the 17-character vehicle identification number.
2. To improve accuracy, append the model year: https://vpic.nhtsa.dot.gov/api/vehicles/decodevin/{VIN}?format=json&modelyear={year}; NHTSA strongly recommends including the model year because some WMI codes were reassigned across years.
3. Parse the Results array in the JSON response; each element contains a Variable (field name) and a Value (decoded value). Key fields include Make, Model, ModelYear, VehicleType, BodyClass, EngineModel, FuelTypePrimary, DriveType, TransmissionStyle, and GVWR.
4. Check the ErrorCode and ErrorText fields in the response; an error code of 0 indicates a clean decode, while codes 1-11 indicate partial or failed decodes.
5. For batch decoding, use POST https://vpic.nhtsa.dot.gov/api/vehicles/decodevinbatch/ with a form body of DATA={VIN1,year1;VIN2,year2}&format=json to decode up to 50 VINs per request.
6. The API is free and does not require authentication or API keys; rate limits are not publicly documented, so implement polite polling with delays between bulk requests.