> ## Documentation Index
> Fetch the complete documentation index at: https://docs.numeral.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Introduction

> The Numeral API for tax calculations (2025-05-12)

<Note>Make sure you generate an API key before making any requests. See [API Keys](/essentials/api-keys) for details.</Note>

## Overview

The Numeral API allows you to calculate and collect sales tax for your business. With our API, you can:

* Get tax information for products and addresses
* Record completed sales
* Handle refunds
* Manage products and customers
* Support business-to-business (B2B) transactions
* Configure automatic tax collection behavior

## Authentication

All API endpoints are authenticated using Bearer tokens. Include your API key in the Authorization header of all requests:

```bash theme={null}
curl --request POST \
  --url https://api.numeralhq.com/tax/calculations \
  --header 'Authorization: Bearer YOUR_API_KEY' \
  --header 'Content-Type: application/json' \
  --header 'X-API-Version: 2025-05-12' \
  --data '{ ... }'
```

## Base URL

All API requests should be made to:

```
https://api.numeralhq.com/
```

## API Version

This documentation covers the `2025-05-12` API version. You must explicitly specify this version in your API requests by including the `X-API-Version` header:

```bash theme={null}
--header 'X-API-Version: 2025-05-12'
```

<Note>
  If you don't specify a version header, requests will default to the `2024-09-01` version.
</Note>

## New Features in 2025-05-12

### Customer Types

Support for business-to-business (B2B) transactions with the `customer.type` field:

* `BUSINESS` - Business customer (requires tax IDs)
* `CONSUMER` - Consumer customer (default)

### Tax IDs

When `customer.type` is set to `BUSINESS`, you must provide tax identification:

* Supports VAT and GST tax IDs
* Required for `BUSINESS` type customers
* Not allowed for `CONSUMER` type customers

### Automatic Tax

Control over tax collection and registration with the `order_details.automatic_tax` field:

* `auto` - Return tax rates everywhere you have an active registration
* `disabled` - Always return 0 tax regardless of thresholds

### Expanded Currency Support

This version supports all currencies from 2024-09-01 plus 22 additional currencies including GBP, AUD, JPY, and more.

For a complete list of supported currencies, see the [Currencies documentation](/essentials/currencies).