# Customise the Widget

{% hint style="info" %}
All query parameters used in your integration must be [URL-encoded](https://www.w3schools.com/tags/ref_urlencode.ASP) to ensure they work correctly. For example use `satoshi%40blockchain.com` for email addresses. 
{% endhint %}

## Mandatory Query Parameters

The only parameter you need when loading the widget is the API Key, this links activity in that widget to your account. 

For more ways to customise your widget, see our document on [Optional Customisation](/pay/getting-started/customise-the-widget/optional-customisation.md).

<table><thead><tr><th width="202">Parameter</th><th>Description</th></tr></thead><tbody><tr><td><code>apiKey</code><br><mark style="color:green;">required</mark></td><td>Use this parameter to initiate the widget for your app. This is how we track customer activity to your account and load all your customizations. </td></tr></tbody></table>


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# 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://docs.blockchain.com/pay/getting-started/customise-the-widget.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.