Money Flow Tracking
The API aims at tracking the money flow so it can reconstitute the performance.
First declare clients. A disbursement should be tracked against a client. Money has been paid to purchase or loaned to someone, so we need identification for reconciliation.
Payments are made on a disbursement to repay it. It can be one or several, paid by client, insurer, or whoever. Any amount effectively received should be tracked as payment to a disbursement to calculate overall performance.
Operation is the underlying of the purchase or the loan. For purchase, that means the goods purchase. For a loan, it means the asset or commercial operation made that needs financing.