> For the complete documentation index, see [llms.txt](https://documentation.vatzen.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://documentation.vatzen.com/api.md).

# API Description

- [VAT Rates](https://documentation.vatzen.com/api/vat-rates.md): Obtain official EU VAT rates, full and reduced, for different categories.
- [VAT Number Validations](https://documentation.vatzen.com/api/validate-vat-number.md): Highly-secured, real-time EU VAT number validation that allows you to check the VAT number for a business. It's helpful when you sell to business customer and do not need to add VAT.
- [VAT Prices Calculations](https://documentation.vatzen.com/api/calculate-price.md): Using our price endpoints, you may request the API to calculate VAT compliant prices for you.
- [Generate Invoce](https://documentation.vatzen.com/api/generate-invoce.md): We created an invoicing service strictly in accordance with the requirements for VAT compliant invoicing published by the EU tax authorities. You can easily issue invoices VIA our API or dashboard.


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# Agent Instructions
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## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://documentation.vatzen.com/api.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.