Sales Tax Lookup API

Query sales tax rates by state, county, and city with a single REST call. FIPS-normalized data ensures consistent, unambiguous jurisdiction identification across every lookup.

State & County Lookup

Every API response includes both the human-readable county name and the FIPS code, giving you two reliable ways to identify the jurisdiction. The rate breakdown separates state, county, city, and district components so you can see exactly how the total rate is calculated.

This granularity is essential for businesses that need to remit collected taxes to multiple jurisdictions or generate detailed tax reports by county.

Multi-State Support

The API covers all 50 US states with a unified interface. Whether you are querying a state with complex local tax structures like Colorado or a flat-rate state like Indiana, the response format is identical.

This consistency simplifies integration. Your code does not need state-specific parsing logic -- the same request format and response schema works everywhere.

FIPS Normalization

County names are notoriously inconsistent across data sources. “St. Louis” vs “Saint Louis,” “DuPage” vs “Du Page” -- these variations create matching failures in systems that rely on string comparison.

SalesTaxAPI normalizes all jurisdictions to FIPS codes, the Federal Information Processing Standard used by the US Census Bureau. Each county has a unique 5-digit code that never changes, regardless of how the name is spelled.

Consistent JSON Responses

California (complex local taxes)
{
  "state": "CA",
  "zip": "90001",
  "total_rate": 0.095,
  "breakdown": {
    "state_rate": 0.0725,
    "county_rate": 0.0025,
    "city_rate": 0,
    "district_rate": 0.02
  },
  "county": "Los Angeles County"
}
Indiana (flat statewide rate)
{
  "state": "IN",
  "zip": "46201",
  "total_rate": 0.07,
  "breakdown": {
    "state_rate": 0.07,
    "county_rate": 0,
    "city_rate": 0,
    "district_rate": 0
  },
  "county": "Marion County"
}

Explore State-Level Rates

Texas →California →Florida →Illinois →Utah →

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Frequently Asked Questions

Can I look up rates for multiple states?
Yes. The API supports lookups across all 50 US states. You can query any state and ZIP combination in a single request. For batch lookups, you can make concurrent API calls.
How are county names normalized?
County names are normalized to a consistent format and mapped to FIPS codes, which are unique 5-digit identifiers assigned by the federal government. This eliminates ambiguity from spelling variations or name changes.
What format do API responses use?
All responses use consistent JSON formatting with the same structure regardless of the state queried. Fields include state, zip, total_rate, a rate breakdown object, county name, and metadata like last_updated and confidence.
Does the API support address-level lookups?
The API currently supports state + ZIP code lookups. ZIP codes are resolved to the most accurate jurisdiction using FIPS-based mapping with confidence scoring.