# Device Registration

Registering a device links the API key to a specific phone, computer, or  in the case of the API a server. 

By using `POST /device-server`, bunq ensures that only pre-approved machines can make API calls. This approach is crucial in banking, where unauthorized access could lead to financial fraud. Unlike simple API keys, this extra layer significantly **reduces attack surfaces** by restricting access to known, registered devices.

{% hint style="warning" %}
Ensure you have a **bunq API Key**. You can generate one from the bunq APP if you haven't already.
{% endhint %}

#### IP addresses

When you use a standard API Key, the `DeviceServer` and `Installation` are linked to the IP address where they were created. You won’t be able to add new IP addresses later.

Using a Wildcard API Key gives you the freedom to make API calls from any IP address after the `POST device-server`. You can switch to a Wildcard API Key by tapping on “Allow All IP Addresses” in your API Key menu inside the bunq app. You can also programatically switch to a Wildcard API Key by passing your current ip and a `*` (asterisk) in the `permitted_ips` field of the device-server POST call. 

Payload example:

```json
{
	"description": "My awesome APP",
	"secret": "{api_key}",
	"permitted_ips": ["1.2.3.4", "*"]
}
```

{% hint style="info" %}
bunq currently only accepts IPV4 addresses. IPV6 is not supported right now.
{% endhint %}

#### Code samples for the device-server endpoint:

{% hint style="warning" %}
Pass the `installation_token` received in the last step as value for the header `X-Bunq-Client-Authentication` to authenticate yourself in this endpoint.
{% endhint %}

{% openapi src="/files/xJ3v0GinyfONRbxz8Srh" path="/device-server" method="post" %}
[swagger.json](https://346554585-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FGE9Y1hc6C24r4Hen6KFH%2Fuploads%2FIUa888wk2qwhos5DXTS3%2Fswagger.json?alt=media\&token=020e751b-2a4b-4993-8247-1f0b9fab0bf5)
{% endopenapi %}

### What's next

With the `installation_token` in hands, we are able to authenticate ourselves and register our device for future endpoint calls. 


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