# Register OAuth Client

Before you can start the OAuth authorization flow with bunq, you need to register an OAuth client. This client represents your application and provides the necessary credentials (`client_id` and `client_secret`) to securely authenticate users.

#### How to Create an OAuth Client

To create an OAuth client, send a `POST` request to:

```
POST /user/{user_id}/oauth-client
```

Replace `{user_id}` with your bunq user ID.

Then it will look like this:<br>

```
curl -X POST "https://api.bunq.com/v1/user/{user_id}/oauth-client" \
  -H "Content-Type: application/json" \
  -H "Cache-Control: no-cache" \
  -H "User-Agent: YourServiceName" \
  -H "X-Bunq-Language: en_US" \
  -H "X-Bunq-Region: nl_NL" \
  -H "X-Bunq-Geolocation: 0 0 0 0 000" \
  -H "X-Bunq-Client-Authentication: your_session_token" \
  -H "X-Bunq-Client-Request-Id: 550e8400-e29b-41d4-a716-446655440000" \
  -H "X-Bunq-Client-Signature: base64_encoded_signature_of_payload" \
  -d '[{
        "status": "ACTIVE",
        "display_name": "My Cool App",
        "redirect_url": "https://myapp.com/oauth/callback"
      }]'
```

Once you have that oauth client registered you can retrieve it's details by repeating the same API call but then as a GET request the response will contain the client\_id and client\_secret. Another item to keep track of is the ID of the oauth client. You may want to use it later in a PUT request to update the redirect URL

{% hint style="warning" %}
Be aware that each bunq user can only have 1 oauth client at a time. You'll get errors if you try to register a second one. As such you want to keep track of the ID so you can update the initial oauth client.&#x20;
{% endhint %}