# Pay Kit Overview

Pay Kit is Cash App Pay’s JavaScript SDK that allows you to accept Cash App Pay online (both on the web and mobile).
Here are some of the things that you can do using Pay Kit:

* Rendering Cash App Pay button to an HTML element
* Customize the Cash App Pay button
* Fully managed and branded UI
* Advanced controls to support:
  * Validating a customer’s information
  * Using custom elements in checkout
  * Upselling to the customer

<img src="https://files.buildwithfern.com/cash-app.docs.buildwithfern.com/2026-01-27T23:03:44.161Z/cash-api-docs/assets/images/easy-name.png" alt="Screenshot 2023-01-12 at 9.42.58 AM.png" />