Creates a new Checkout Payment Button configuration for PayPal, Stripe, or StripeConnect.
API Key required for authorization (mandatory for all endpoints)
Name of the product associated with the checkout button
Amount for the payment (decimal string)
Currency code (e.g., USD, EUR)
External payment provider
PayPal, Stripe, StripeConnect Type of payment
one_time, subscription Indicates live or sandbox mode
Description of the product or service
Billing interval for subscriptions
Required if PaymentMethod is StripeConnect. Must be between 0.01 and 100.