Resolve a US ZIP code to the census tract(s), county, CBSA...
Resolve a US ZIP code to the census tract(s), county, CBSA (metro), and congressional district it covers — each with HUD-USPS allocation ratios (by residential, business, other, and total address counts). A ZIP is a mail-delivery route set, not a polygon, so it spans multiple geographies; the ratios tell you how much of the ZIP falls in each — the canonical join when you have a ZIP but a dataset is keyed by county/tract/district. Source: HUD-USPS ZIP Crosswalk (public domain).
Request
- Base URL: https://2s.io
- URL: https://2s.io/api/geo/zip-resolve
- Auth: API key in header PAYMENT-SIGNATURE
Query parameters
5-digit US ZIP code, e.g. 90210.
Try before you buy. Set to 1 for one free real call per endpoint per hour — no wallet or payment needed — to verify the endpoint before paying. Equivalent to sending the "X-2s-Trial: 1" request header. Listed only on operations that offer a trial; the others always answer 402.
Response
Changes
No recorded changes to this operation across all 1 revision of this API.