By Postal Code
All tax rates that overlap a U.S. ZIP code
Look up every sales tax rate that applies inside a U.S. 5-digit ZIP code. Unlike By Address and By Lat / Lng, which each return a single door-level rate, a postal code request returns every applicable rate for each jurisdiction that overlaps the ZIP, with no geocoding and no door-level disambiguation.
Postal code lookups are not door-level accurate. They don’t adjust for unincorporated areas or special tax jurisdictions, and a single ZIP can span multiple cities, counties, and districts. If you need a single authoritative rate for tax collection or compliance filings, use By Address or By Lat / Lng instead.
For transactional use (calculating tax on an order, filing returns), always prefer an address or lat/lng lookup.
Send the ZIP in the postalcode query parameter.
You must also authenticate with your API key via the X-API-Key header
(recommended) or the key query parameter.
Postal code lookups don’t accept countryCode, taxabilityCode,
sat_item_total, or historical. Those parameters
apply only to address and lat/lng lookups. For Canadian rates, use
By Address or By Lat / Lng with
countryCode=CAN.
Because a ZIP can overlap multiple jurisdictions, the response contains
a results array with one entry per applicable rate:
addressDetail is always null for postal code lookups: there’s no
single address to normalize. If you need a normalized address, use an
address or lat/lng lookup.
Northeastern ZIPs like Boston’s 02101 are strings, not numbers.
If your client library serializes the value as an integer, the
leading zero is stripped and the lookup will fail or return a
different ZIP’s results.
Don’t pick the first result blindly. Some ZIPs span two or more cities or special districts. If you must pick one, match on city or county if you have any additional context; otherwise prompt the user or upgrade to an address lookup.
Postal code rates are not adjusted for unincorporated pockets or special district overlays. Using them for tax collection on a real transaction risks under- or over-collecting, both of which create compliance problems. Use address or lat/lng for anything that will end up on a return.
Only the 5-digit ZIP is accepted. If you have a ZIP+4, drop the +4
suffix or (better) use the associated street address for a door-level
lookup.