Sales Tax Calculator API

About the Sales Tax Calculator API

Use it at checkout, on invoices or in quotes: send the amount and the ZIP code, and it looks up the current combined rate for that ZIP, applies it, and rounds the tax to the cent. A state code works too and applies the statewide base rate only. For ZIP lookups, paid plans add the region name and a breakdown with each jurisdiction's rate and its share of the tax, the split you need for itemized tax lines. It applies the general sales tax rate to the amount you send; product exemptions, shipping taxability and nexus are left to you.

What people use it for

E-commerce Checkout

Calculate accurate sales tax at checkout based on customer shipping address for tax-compliant transactions

Point of Sale Systems

Integrate real-time tax calculations into POS systems for accurate receipt generation

Invoice Generation

Automatically calculate and add sales tax to invoices based on customer location

Price Quoting

Generate accurate price quotes that include applicable sales tax for any US location

Ways to call it

One endpoint, many ways in — REST with JSON, XML, YAML and CSV, plus GraphQL and an MCP interface for AI agents.

JSON

Default REST response

XML

Markup format

YAML

Human-readable

CSV

Tabular export

Beta

GraphQL

Query language

New

MCP

For AI agents

How it compares

Side by side with the tools people weigh Sales Tax Calculator against — what each one is better at, in plain terms.

Request parameters — GET /v1/salestaxcalculator

Sent in the query string. Premium parameters are accepted on every plan but only take effect on plans that include them. Anything not listed here is dropped rather than passed through.

Required

Optional

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curl "https://api.apiverve.com/v1/salestaxcalculator?amount=100&zip=90210&state=CA" \
  -H "x-api-key: YOUR_API_KEY"

Authentication

Send your key in the x-api-key header. That is the only auth step — no token exchange, and no per-endpoint scope to configure.

Response — GET /v1/salestaxcalculator

Every APIVerve endpoint returns the same three top-level keys, so one response handler covers your whole integration: status, error and data. Only data changes shape.

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{
  "status": "ok",
  "error": null,
  "data": {
    "amount": 100,
    "taxRate": 0.1025,
    "taxRatePercent": 10.25,
    "taxAmount": 10.25,
    "totalAmount": 110.25,
    "zip": "90210",
    "state": "CA",
    "region": "WEST HOLLYWOOD TOURISM IMPROVEMENT DISTRICT",
    "breakdown": {
      "stateRate": 0.06,
      "countyRate": 0.0025,
      "cityRate": 0.0075,
      "specialRate": 0.0325,
      "stateTax": 6,
      "countyTax": 0.25,
      "cityTax": 0.75,
      "specialTax": 3.25
    }
  }
}

Response fields

Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.

Response headers

Every response carries your balance, so your own code always knows where it stands without polling anything. All four are exposed to browsers through CORS.

Errors

Read the HTTP status first, then error for the specific reason. The body names the parameter that has to change.

What a call costs — 2 credits per call

Credits are shared across every APIVerve API — one balance, one key, one bill. Failed requests never count against it, so a rejected input costs nothing.

Calls are what the credits buy at this API's rate — spend them here, on any of the other APIs, or across both. Nothing is reserved per endpoint.

Zero-code embed — one snippet, no backend

Drop an interactive Sales Tax Calculator form onto any page. The widget calls the API for you, so no key ever appears in your markup and there is nothing to deploy.

Changelog — Sales Tax Calculator API

Every change to this endpoint, newest first. Breaking changes ship as a new version and the previous one keeps serving — response fields are added, never removed or retyped in place, so an integration written against v1 keeps working.

Currently v1