> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://ixopay.ferndocs.com/developer-hub/documentation/reference/integration/hosted-fields-payment-js/advanced-guides/overview/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://ixopay.ferndocs.com/_mcp/server.

# Advanced guides

The Advanced Guides section provides in-depth information on integrating our client-side API into your workflow, covering more advanced use cases and customization options. This section includes links to advanced guides on specific topics, such as auto filling card data, CVV refreshing, and styling your form. These guides are designed to help you get the most out of our API and customize it to meet your specific needs. Whether you're a new or experienced user, this section provides a wealth of information on how to take your integration to the next level.

#### [CVV refreshing](https://documentation.ixopay.com/docs/reference/integration/payment.js/advanced-guides/cvv-refreshing)

How to use CVV refreshing in payment.js to re-collect a CVV code for card-on-file transactions when the stored token lacks the verification code.

#### [Auto-fill card data](https://documentation.ixopay.com/docs/reference/integration/payment.js/advanced-guides/auto-fill-card-data)

Make browser and password manager autofill work in payment.js card fields, which require special setup because sensitive inputs render inside iframes.

#### [Form styling](https://documentation.ixopay.com/docs/reference/integration/payment.js/advanced-guides/form-styling)

Style payment.js card input fields to match your checkout form design, including support for focus, hover, and placeholder styles.