E-Commerce/Shopping Cart Plugin Integrations
WP Simple Pay is a stand-alone product and does not integrate with other e-commerce or shopping cart plugins.
Most e-commerce/shopping cart plugins now include their own Stripe integration.
If you are using WooCommerce, we recommend using their native Stripe extension: https://woocommerce.com/products/stripe/
Theme and Page Builder Integrations
In general, WP Simple Pay is compatible with all themes and page builders. However, at times you’ll want to use your theme’s styled buttons to launch a custom overlay or Stripe Checkout payment form. There are a few ways to do this.
See this document for more information: https://docs.wpsimplepay.com/articles/launch-overlay-externally/
The article linked above details adding custom code to your WordPress site and is intended for developers.