SalesTaxIQ API Documentation

Getting Started

SalesTaxIQ provides enterprise-ready tax determination endpoints for U.S. address-level sales tax calculation with clear, auditable rate detail.

This reference is optimized for implementation teams that need fast onboarding, predictable responses, and operational confidence in production.

To launch in production:

1. Sign up for an account
2. Choose a pricing plan
3. Get your API key
4. Run test lookups against representative shipping addresses
5. Move API key handling to your server-side infrastructure

Authentication

All API requests require authentication using your API key. Include your key in the request headers:

Authorization: Bearer sk_YOUR_API_KEY

Use separate API keys for sandbox and production environments, and rotate keys on a regular security schedule.

Rate Lookup API

Endpoint

Request Format

{
  "city": "Menlo Park",
  "state": "CA",
  "street": "1 Hacker Way",
  "zip": "94025"
}

Response Format

{
  "tax_rate": 9.375,
  "rate_details": [
    {
      "tax_agency": "California, San Mateo County District",
      "tax_rate": 2.125
    },
    {
      "tax_agency": "San Mateo County",
      "tax_rate": 1
    },
    {
      "tax_agency": "California State",
      "tax_rate": 6.25
    }
  ]
}

Authentication

Include your API key in the Authorization header:

Authorization: Bearer sk_your_api_key

Error Responses

Example Request (cURL)

curl -X POST \
  /api/v1/rates \
  -H 'Authorization: Bearer sk_your_api_key' \
  -H 'Content-Type: application/json' \
  -d '{
    "city": "Menlo Park",
    "state": "CA",
    "street": "1 Hacker Way",
    "zip": "94025"
  }'

Code Examples

import requests

api_key = 'sk_your_api_key'
url = '/api/v1/rates'

headers = {
    'Authorization': f'Bearer {api_key}',
    'Content-Type': 'application/json'
}

data = {
    'city': 'Menlo Park',
    'state': 'CA',
    'street': '1 Hacker Way',
    'zip': '94025'
}

response = requests.post(url, json=data, headers=headers)
print(response.json())

const axios = require('axios');

const apiKey = 'sk_your_api_key';
const url = '/api/v1/rates';

const data = {
  city: 'Menlo Park',
  state: 'CA',
  street: '1 Hacker Way',
  zip: '94025'
};

axios.post(url, data, {
  headers: {
    'Authorization': `Bearer ${apiKey}`,
    'Content-Type': 'application/json'
  }
})
.then(response => console.log(response.data))
.catch(error => console.error(error));

package main

import (
    "bytes"
    "encoding/json"
    "fmt"
    "net/http"
)

func main() {
    apiKey := "sk_your_api_key"
    url := "/api/v1/rates"

    data := map[string]string{
        "city":   "Menlo Park",
        "state":  "CA",
        "street": "1 Hacker Way",
        "zip":    "94025",
    }

    jsonData, _ := json.Marshal(data)

    req, _ := http.NewRequest("POST", url, bytes.NewBuffer(jsonData))
    req.Header.Set("Authorization", "Bearer "+apiKey)
    req.Header.Set("Content-Type", "application/json")

    client := &http.Client{}
    resp, err := client.Do(req)
    if err != nil {
        panic(err)
    }
    defer resp.Body.Close()

    var result map[string]interface{}
    json.NewDecoder(resp.Body).Decode(&result)
    fmt.Println(result)
}

Try It Out

Production Readiness

Before launch, make sure your integration includes operational and compliance guardrails.

Error Handling

The API uses conventional HTTP response codes to indicate success or failure of requests: