Suspected duplicate transactions
In order to protect Helcim merchants against accidental duplicate transactions, the Helcim system has functionality built in that will automatically decline transactions that it suspects are duplicates. This check was put in place to avoid duplicate transactions processed through Helcim services like the Virtual Terminal, Helcim App, and the Helcim API.
How does the Suspected Duplicate check work?
The suspected duplicates process is a secondary process to Idempotency Keys. This check will trigger even in instances where the flagged duplicate transaction has a different idempotency key from the original transaction.
The Suspected Duplicate check will review any successful transactions within 5 minutes where the cardNumber
, cardholderName
, and amount
match a previous transaction within that time period.
Suspected duplicate transactions will have a transaction status
of "DECLINED" returned in the transaction response object, with an errors
message stating "Transaction Declined: DECLINED - Suspected duplicate transaction in the last 5 minutes.".
// Example payment,= declined due to failing suspected duplicate check
{
"transactionId": 21071575,
"dateCreated": "2024-07-13 16:07:54",
"cardBatchId": 0,
"status": "DECLINED",
"user": "Helcim System",
"type": "purchase",
"amount": 10.99,
"currency": "USD",
"avsResponse": "",
"cvvResponse": "",
"errors": "Transaction Declined: DECLINED - Suspected duplicate transaction in the last 5 minutes."
}
Updated about 2 months ago