Skip to main content

​
Authentication

To use the Taxwire API there is minimal setup or overhead. All you need is an authentication header X-API-Key (see authentication for details).

​
API versioning

To ensure best result, we also recommend you use a version header so you can be confident about what the response will be. Visit the versioning page for more information.

​
Quickstart

You are now ready to make your first API request. Here is a simple, yet complete example of how to make a calculation request. All you need is to replace the header X-API-Key and Taxwire-Version with real values. 
curl -X POST \
  --url https://api.taxwire.com/calculations \
  --header 'Content-Type: application/json' \
  --header 'X-API-Key: REPLACE_WITH_YOUR_API_KEY' \
  --header 'Taxwire-Version: hydrogen.2025-04-15' \
  --data '{
    "line_items": [
      {
        "quantity": "1",
        "unit_price": "100",
        "customer": {
          "address": {
            "line1": "123 Main St",
            "city": "San Francisco",
            "state": "CA",
            "country": "US",
            "postal_code": "94105"
          }
        }
      }
    ]
  }'
It’s that easy! Want to get down to the nitty gritty? Check out our more detailed guides or individual API reference pages.