Online Duplicate Checking

When processing an Online transaction, the system acts to detect duplicate transactions for the following transaction types: Auth Reversal, Capture, Force Capture, Capture Given Auth, Credit, Sales, eCheck Credit, eCheck Sales, eCheck Void, and Void, as well as Gift Card transactions.

For most transactions, the system compares the transaction type, the id attribute from the request, and the credit card number against other Online transactions processed within the previous two days. For transactions that reference other transactions (for example, a deposit referencing an authorization or a refund referencing a deposit), the system compares the transaction type, id attribute, and the card number from the referenced transaction (i.e. the transaction identified by the <cnpTxnId> element) against other Online transactions processed within the previous two days.

The system only performs duplicate detection against valid transactions. For example, if a Capture request matches a declined Capture from the previous day, the system would not count it as a duplicate, because the declined Capture was not a valid transaction.

While it is uncommon, under certain circumstances network latency may cause a duplicate Sale transaction to go undetected. This can occur if you submit a second, duplicate Sale transaction while the response from the network for the Authorization portion of the first transaction is sufficiently delayed such that the first Sale has not been recorded as a valid transaction in the system.

If you elect to submit Online Sale and/or Credit transactions, Worldpay recommends a timeout setting of not less than 60 seconds to reduce the chances of undetected duplicate transactions.

If the system determines a transaction to be a duplicate, The duplicate transactions appears in the Declined Transaction report with a Response Reason Code of 251 - Duplicate Transaction. You can access this report in Worldpay eComm iQ or via the Worldpay eComm Secure Scheduled Reports. The iQ version provides information in near real-time, while the SSR version runs daily, providing information for the transaction submitted the previous day.

If you do not receive a response for a submitted transaction, Worldpay recommends you use the queryTransaction to determine the status of the original transaction (see Status Query Transactions (Online Only)).