# 4 Domains API: How to retrieve TLD specific data

<span>*This is a series of articles dedicated to demonstrating how to get acquainted with Openprovider Domains API methods.* </span> *To get more information about our API in general, please use our [documentation portal](http://docs.openprovider.com) as your reference.*

Additional domain fields (also commonly referred to as Extended Attributes) define the information required by domain registries for a given TLD.

While most extensions can be registered with just the basic contact data (company name, contact name, address, telephone number, and e-mail address), several extensions require additional contact information in order to register a domain name. When a domain registry requires the information, a domain name will fail to register successfully unless the values are provided.

Typical information requested by domain registries includes things such as Registrant Legal Type, Registered Entity Name, etc.

![Entering Geo Fence icon](https://openprovider.help/uploads/images/gallery/2026-08/embedded-image-2twazdcx.png)<span>Use the endpoint path below. The base URL is determined by both the target environment and the API version.</span>

```
<span><strong>GET</strong> <a href="https://docs.openprovider.com/doc/all">{base_url}</a>/domains/additional-data</span>
```

<div id="bkmrk-request-values-name-"><details><summary>REQUEST VALUES</summary>

<table><tbody><tr><td>**<span>Name</span>**</td><td>**<span>Type</span>**</td><td>**<span>Description</span>**</td></tr><tr><td>domain.extension</td><td>string</td><td>**Required**<span>.</span></td></tr></tbody></table>

</details><div id="bkmrk-request-examplecurl-"><div><details><summary>REQUEST EXAMPLE</summary>

```
curl -X GET \<br></br> 'https://api.openprovider.eu/v1beta/domains/additional-data?domain.extension=no' \<br></br> -H 'Authorization: Bearer eca82663f*******76d063d8f6196' \
```

</details></div><details><summary>RESPONSE EXAMPLE</summary>

```
{<br></br>"code": 0,<br></br>"desc": "",<br></br>"data": [<br></br>{<br></br>"name": "company_registration_number",<br></br>"description": "Company registration number. Required in case if domain requester is a legal entity",<br></br>"required": false,<br></br>"type": "text"<br></br>},<br></br>{<br></br>"name": "company_registration_number",<br></br>"description": "Company registration number. Required in case if domain requester is a legal entity",<br></br>"required": false,<br></br>"type": "text"<br></br>}<br></br>]<br></br>}
```

</details></div></div>