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 field. Idempotency fields stay unique without a time limit.

Idempotency fields

The following tables list the APIs that need idempotency control, 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: ACQP > Alipay+

For APIs that are used by the ACQP 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
pay (User-presented Mode Payment)	paymentRequestId	paymentAmount, paymentMethod.paymentMethodType, and order.orderAmount
pay (Merchant-presented Mode Payment -Entry Code)
pay (Merchant-presented Mode Payment - Order Code)
pay (Cashier Payment)
pay (Auto Debit)
refund	refundRequestId	refundAmount and paymentRequestId, or refundAmount and paymentId
cancelPayment	paymentRequestId	N/A
prepare	authClientId and referenceAgreementId Note: authClientId and referenceAgreementId are jointly used for idempotency control.	ALL the other request parameters
cancelToken	accessToken	N/A
registration	registrationRequestId	N/A
declare	customsDeclarationRequestId	N/A
responseRetrieval	disputeRequestId	N/A
responseEscalation	disputeRequestId	refundType and refundAmount

Direction: Alipay+ > ACQP

For APIs that are used by Alipay+ to call the ACQP, the ACQP 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
userInitiatedPay	codeValue	customerId
initiateRetrieval	disputeRequestId	paymentRequestId
initiateEscalation	disputeRequestId	paymentRequestId