Idempotency

An API call is idempotent if the action is performed only once no matter how many times the API call is retried.

Idempotency helps to avoid unwanted duplication in case of failures and retries. For example, idempotency can guarantee that the payment is charged only once if the same API payment call is retried multiple times in the case of a timeout error.

In Alipay+, API idempotency is enabled by an idempotency parameter. Idempotency parameters stay unique without a time limit.

Idempotency parameters

The following tables list the idempotency parameters of APIs and key parameters that are checked for consistency in idempotency control. For detailed information, see the specific API chapter.

Direction: Alipay+ > MPP

For APIs that are used by Alipay+ to call the MPP, the MPP decides the idempotency parameters and key parameters that are checked for consistency. The following table lists the APIs that need idempotency control, the idempotency parameters of APIs, and recommended key parameters that are checked for consistency in idempotency control:

Interface	Idempotency parameter	Key parameter to check consistency
pay	paymentRequestId	paymentAmount, payToAmount, surchargeInfo, paymentMethod, and paymentPromoInfo
refund	refundRequestId	refundAmount, refundFromAmount, refundPromoInfo, and surchargeInfo
cancelPayment	paymentRequestId	N/A
prepare	authClientId and referenceAgreementId Note: It is recommended that authClientId and referenceAgreementId are jointly used for idempotency control.	authClientName, referenceMerchantId, authRedirectUrl, and scopes
cancelToken	accessToken	N/A
responseRetrieval	disputeRequestId	N/A
responseEscalation	disputeRequestId	refundType and refundAmount

Direction: MPP > Alipay+

For APIs that are used by the MPP to call Alipay+, Alipay+ decides the idempotency parameters and key parameters that are checked for consistency. The following table lists the APIs that need idempotency control, idempotency parameters of APIs, and key parameters that are checked for consistency in idempotency control:

Interface	Idempotency parameter	Key parameter to check consistency
notifyPayment	paymentRequestId	paymentAmount, paymentResult, paymentId, payToAmount, customerId, and customsDeclarationAmount
userInitiatedPay	paymentRequestId (response parameter)	N/A
initiateRetrieval	disputeRequestId	paymentRequestId
initiateEscalation	disputeRequestId	paymentRequestId