> This page is for version v6.0 (default).
> For other versions, use one of these documentation indexes:
> - v6.0 (default): https://docs.zip.tax/v-6-0/llms.txt
> - v5.0: https://docs.zip.tax/v-5-0/llms.txt

> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.zip.tax/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.zip.tax/_mcp/server.

# 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](by-address)

Recommended

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

#### [By Lat / Lng](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](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](by-address)         |
| Just street + ZIP (no city/state) | [By Address](by-address)         |
| Verified geocoded coordinates     | [By Lat / Lng](by-lat-lng)       |
| Only a ZIP code                   | [By Postal Code](by-postal-code) |
| A storefront with a known lat/lng | [By Lat / Lng](by-lat-lng)       |

> **Info**
>
> 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.

#### Header (recommended)

```bash
curl -H "X-API-KEY: YOUR_API_KEY" \
  "https://api.zip-tax.com/request/v60?address=..."
```

#### Query parameter

```bash
curl "https://api.zip-tax.com/request/v60?key=YOUR_API_KEY&address=..."
```

> **Info**
>
> Don't have an API key yet? Create a free account at
> [platform.zip.tax](https://platform.zip.tax).

## Base URL & versions

```http
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](/api-reference) for the full
response schema of each version.