This section outlines the mechanics and mapping matrices for transaction fee deduction rules within the OneKhusa Payment Gateway ecosystem. These rules are configured at the merchant account level to control whether transaction fees are dynamically borne by the customer or absorbed by the merchant for both collection (inbound/payment) and disbursement (outbound/payout) financial workflows.

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Applicable Fee Deduction Rules

Rule CodeRule NameBehavior & Operational Logic
CCCharge to the Customer
  • Collection Flow: Transaction fees are added on top of the base (original) transaction amount. The customer pays the total aggregated amount, ensuring the merchant receives the exact base amount. For example:
    • Base Transaction Amount: MWK30,000.00
    • Transaction Fee: MWK1,500.00
    • Total Amount Charged: MWK31,500.00
  • Disbursement Flow: The transaction fee is deducted from the specified payout amount before execution. The customer receives the net remaining balance.
CMCharge to the Merchant
  • Collection Flow: Transaction fees are deducted directly from the base transaction amount received. The merchant’s account balance is updated with the remaining net amount. For example:
    • Base Transaction Amount: MWK30,000.00
    • Transaction Fee: MWK1,500.00
    • Net Balance Settled: MWK28,500.00
  • Disbursement Flow: Transaction fees are debited separately from the merchant’s operational account balance. The end-customer (beneficiary) receives the full, unaltered original disbursement amount. For example:
    • Base Transaction Amount: MWK30,000.00 (Received fully by customer)
    • Fee Deduction: MWK1,500.00 (Debited from Merchant Account Balance)

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Transaction Type Integration Matrix

ModuleTransaction TypeSupported RulesArchitectural Constraints & Comments
DisbursementPayout (Outbound Credit Transfer)CC, CMFully supported. Fees can either be deducted from the customer or charged to the merchant account balance.
DisbursementInbound Push PaymentCMCC rule is NOT supported. Because this push payment is initiated externally by the bank/MNO for OneKhusa to authorize a payment, the original transaction amount cannot be altered dynamically to pass fees to the customer.
CollectionAccount Top-up (Inbound Credit Transfer)CMCC rule is NOT supported. Transfers are pushed from the Bank/MNO to OneKhusa to credit the merchant account. Original transaction amounts are fixed on origin, and fees are computed immediately upon transaction receipt and deducted from merchant balance.
CollectionPush Payment (Outbound USSD Prompt/Bank Transfer Push)CC, CMFully supported. Initiated directly by OneKhusa to a Bank/MNO to authorize immediate push payment workflows.
CollectionRequest-To-Pay Timed Account Number (TAN) PaymentCMCC rule is NOT supported. Transfers are pushed from the Bank/MNO to OneKhusa via a temporary TAN to credit the merchant account. Original transaction amounts are fixed on origin, and fees are computed immediately upon transaction receipt and deducted from settlement balance.
CollectionCard PaymentCM CCFees are natively handled and applied through the card schemes (VISA/MasterCard networks) as a clear deduction from the gross transaction value upon payment receipt verification. The merchant account will receive the net transaction amount.

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Implementation Guidelines for Developers

  • Rule Evaluation Timing: Fee rules are evaluated at the moment of payment routing initiation (outbound) or immediately upon payment receipt (inbound).
  • Validation Errors: Attempting to submit an API payload containing feeDeductionRule: “CC” on endpoints mapped exclusively to CM (Inbound Credit Transfers) will result in an immediate 400 Bad Request validation error messages