REST API Overview

The Ziptax REST API returns U.S. (and, on supported plans, Canadian) sales tax rates for a given location. Every lookup hits the same base endpoint (GET https://api.zip-tax.com/request/v60) and you choose the lookup method by which query parameter(s) you supply.

Choose a lookup method

By Address

Street address → a single door-level rate. Ziptax geocodes the address and applies unincorporated-area and special-district adjustments. Recommended for most integrations.

By Lat / Lng

Coordinates → a single door-level rate. Skip geocoding if you already have verified lat/lng from your own pipeline.

By Postal Code

5-digit ZIP → all rates that overlap the ZIP. Useful for lookups where you don’t have a street address, but less accurate than address or lat/lng.

Decision guide

If you have…	Use
A full customer shipping address	By Address
Just street + ZIP (no city/state)	By Address
Verified geocoded coordinates	By Lat / Lng
Only a ZIP code	By Postal Code
A storefront with a known lat/lng	By Lat / Lng

Address and lat/lng lookups return a single door-level rate that has been adjusted for unincorporated areas and special tax jurisdictions. Postal code lookups return every rate that overlaps the ZIP, with no door-level accuracy. Use address or lat/lng for compliant tax calculations.

Authentication

Every request needs an API key. You can supply it two ways, and the header is preferred for production clients.

$ curl -H "X-API-Key: YOUR_API_KEY" \
>   "https://api.zip-tax.com/request/v60?address=..."

Don’t have an API key yet? Create a free account at platform.zip.tax.

Base URL & versions

1 https://api.zip-tax.com/request/v60

The version segment (v60) selects the response shape and feature set. Older versions (v50, v40, and earlier) remain available for backward compatibility. See the API Reference for the full response schema of each version.