Mapbox Geocoding API Adds Optional USPS ZIP+4 Postal Code Support in v6

Mapbox has introduced optional USPS ZIP+4 postal code support for its Geocoding API, available starting in API version 6. The feature adds a new boolean parameter called plus4_code, which defaults to false, ensuring full backward compatibility with existing integrations. When enabled, the reverse geocoding endpoint returns a four-digit extension alongside the standard five-digit ZIP code, allowing precise identification of specific buildings or mail delivery points. The addition is aimed at delivery services, logistics firms, e-commerce platforms, and financial institutions that require high-accuracy address data. Not all locations will return a ZIP+4 code — rural areas, PO boxes, and non-US addresses may not have one, in which case the field is simply omitted from the response.