Checkout: Filter Reference« Codex
The WordPress Shopping Cart plugin will fire filter hooks throughout it’s code so that you can hook with custom filters onto these filters hooks while receiving parameters and apply your own functions.
It works exactly like the WordPress Plugin API/Filter Reference by using the
apply_filters() function and the filter hooks are used in the same manner as that of WordPress.
This filter reference is constantly updated with new filter hooks as the plugin is updated so search here or request a new filter hook if you’re looking for something specific.
wpco_get_option_$name- Runs when a specific option is fetched where $name is the name/slug of the option.
wpco_tax_total- Applied to the tax total calculated on an order.
Shopping Cart Filters
wpco_cart_validation- Applied to the cart errors of the shopping cart step.
wpco_shipping_validation- Applied to the shipping errors of the shipping step.
wpco_billing_validation- Applied to the billing errors of the billing step.
checkout_extensions_list- Applied to the list of extension plugins so that they can be altered or an extension can be added to the list.
Payment Method Filters
wpco_pmethod_title- Runs on the title/name of a payment method.
checkout_recurring_pmethods– Filters the available, recurring payment methods.