pmpro_checkout_signon_secure

Force PMPro to login over http or https in case other plugins (like WordPress MU Domain Mapping) conflict with what should be chosen here

pmpro_checkout_start_date

This hook pmpro_checkout_start_date allows you to change the start date of a membership before checkout.

pmpro_discount_code_level

This filter modifies the level  given by a discount code.  It passes the level object and the discount code ID.

pmpro_required_user_fields

Filters the required fields for the Account Information section on the checkout page. Passes the array of field names.

pmpro_confirmation_url

This filter changes the URL to redirect to on confirmation. By default, this redirects to the PMPro Confirmation page with pmpro_url("confirmation", "?level=" . $pmpro_level->id). It also passes the user ID of the current user and the level object.

pmpro_valid_gateways

Modifies the list of valid gateways used by PMPro. By default, it returns the gateway set in Memberships > Payment Settings in the WordPress Dashboard.