How to identify all installments of an installment plan?

When we create an installment plan, we return the installment ID in the installment attribute and each installment has its own payment ID. Then you will receive a PAYMENT_CREATED webhook for each installment, which contains the installment id in addition to the billing payment id. Another way would be to list charges for an installment plan, making a GET call to the endpoint for listing charges for an installment plan.