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A user may purchase a License for themselves by calling the create license endpoint. In order to create a license, some method of payment must be provided. At the moment only one method of payment is supported: "billing". With this payment method, no further payment details are necessary, but the user is charged through the service provider's billing system.
Billing
If the service provider supports billing as a payment method, then they are responsible for handling the billing of the customer separately. A list of all purchased licenses can be obtained through the management API. The order ID of a license uniquely identifies each purchase. This identifier should be used to make sure the user is not billed multiple times for the same purchase.