Pull vehicle valuations via a valuation API

Steps

1. Obtain API access through a formal business agreement; both Kelley Blue Book (b2b.kbb.com) and Black Book provide valuation data exclusively through partner or dealer subscription programs — there is no public self-service API.
2. Once credentialed, authenticate using the API key or OAuth 2.0 credentials provided by your partner agreement and direct API calls to the partner API base URL specified in your contract documentation.
3. Submit a valuation request by providing the VIN or a combination of year, make, model, trim, mileage, and condition grade; the API returns a structured response with retail, trade-in, and private-party values depending on the contracted data set.
4. Incorporate mileage and condition adjustments: most valuation APIs accept a mileage parameter and a condition enum (Excellent, Good, Fair, Poor) that modifies the base value.
5. Cache valuation responses with a short TTL (typically 24 hours or as specified in your contract); market values change daily and caching stale values can lead to incorrect appraisals.
6. For a no-agreement alternative during development, consider open-source vehicle valuation proxies or aggregators such as vehicledatabases.com, which resell or aggregate valuation data, subject to their own terms.