pmpro_checkout_before_change_membership_level

Use this hook to execute custom behavior before the membership level is changed at checkout. This hook is also used by integrated payment gateways for offsite checkout in some cases.

pmpro_setup_new_user

Filter to proceed with setting up the new user and membership after the checkout page is submitted.

pmpro_new_user

Hook to allow custom code to alter the user object before it is created at membership checkout.

pmpro_checkout_new_user_array

Change and/or modify the user data that is created for the user after checkout. This is useful for changing the user login, password, email, and other user data.