# Card-Based Payment Instrument Issuer (CBPII)

{% hint style="success" %}
Heya! Before checking this page, make sure that you [registered yourself as a TPP](/psd2/are-you-a-third-party-provider-tpp-start-here/register-as-a-tpp.md) in our API first.
{% endhint %}

As a CBPII, you are allowed to authenticate in a user’s account to validate the availability of funds for the payment in question.

1. Collect an alias for the bunq user's account (their name and IBAN, email address, or phone number).
2. Check the availability of funds via `POST /user/{userID}/confirmation-of-funds` passing the following information:
   * your `userId`;
   * the amount of money needed for the payment;
   * the name of the bunq user and the IBAN of the account (email address or phone number pointing at the user are also possible).

Here is the full specs of the endpoint:

{% openapi src="/files/xJ3v0GinyfONRbxz8Srh" path="/user/{userID}/confirmation-of-funds" 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 %}


---

# Agent Instructions: 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:

```
GET https://doc.bunq.com/psd2/card-based-payment-instrument-issuer-cbpii.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
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.