Difference between merchantOrderID and cartID

What is the difference between merchantOrderId and cartId? We want to send our payment ID, and it should appear in the reconciliation report to match the transaction with our orders. Which field should we use?

merchantOrderId is the final order ID and is suitable for your use case. It will appear in the reconciliation report. You may use this field.

cartId is typically used by merchants on platforms like WooCommerce or Shopify, where it's auto-generated. It’s mainly used for internal reference.