Capture Pre-auth request

An overview of the Capture Pre-auth request message for iOS.

Our ‘ | Terminal’ application (tap-on-phone) supports Apple Tap to Pay in the UK & the Netherlands


👉 The Capture Pre-auth request is used to capture a pre-authorisation transaction.

The client app must implement a mechanism to send messages using URL schemes and to receive the result in a custom URI callback.

Capture Pre-auth request 

For a typical Capture Pre-auth request, the client app must provide the following information:

Field Description Example
scheme The Viva custom URL scheme, the host and the version. 'vivapayclient://pay/v1'
merchantKey The merchant's key. For successful validation, should not be empty.
Deprecated: you may pass any value.
appId The client app id. 'com.example.myapp'
action Capture Pre-auth transaction. 'capture_pre_auth'
amount The amount to refund in cents, without any decimal digits. If no amount provided, a full refund will be performed. '600' = 6 euro (optional)
referenceNumber The STAN number of the transaction to be captured. '833121' (optional)
orderCode The order code of the transaction to be captured. When provided, it will act as a search parameter and if a transaction with the same order code is found, the capture will take place. If a reference number has also been provided, only the order code will be taken into consideration. '109113919500020' (optional)
shortOrderCode Same as order code but in shorter length, although when provided, it will be reconstructed into a full length order code based on the terminal used. If the original sale has been made in a different terminal, the transaction won’t be retrieved and therefore captured. If both orderCode and shortOrderCode are provided, only the shortOrderCode will be taken into consideration. '1091139195’ (optional)
txnDateFrom Specifies the minimum date on which the transaction search will take place. if txnDateFrom is provided and txnDateTo is not, the current date will be assigned as the value of txnDateTo.

The date should be in ISO 8601 format.
‘2021-03-29T00:00:00.000+0300’ (required if txnDateTo has been set, otherwise optional)
txnDateTo Specifies the maximum date on which the transaction search will take place. if txnDateFrom has not been provided but a txnDateTo has, an error is returned.

The date should be in ISO 8601 format.
‘2021-03-30T00:00:00.000+0300’ (optional)
show_receipt Option to show the receipt screen, before returning to the InterApp, after performing a refund on VW POS. 'true'
show_transaction_result Option to show the transcation result screen, before returning to the InterApp, after performing a capture on VW POS. If show_receipt is set to ‘true’ this value will be neglected, therefore the transcation result screen will be shown. 'true'
protocol The protocol used (internal use only) int_default
callback Your custom URI callback that will handle the result. 'interapp-callback'

The above information elements must create a URI call, such as:

func createCapturePreauthRequest(captureAmount: Decimal?, reference: String?, orderCode: String?, shortOrderCode: String?, dateFrom: String?, dateTo: String?) -> String {

        // construct capture action url
        var capturePreauthActionURL = Constants.captureUrlString // vivapayclient://pay/v1?callback=interapp-callback&merchantKey=SG23323424EXS3&appId=com.vivawallet.InterAppDemo&action=capture_pre_auth

        if let amount = refundAmount {
            capturePreauthActionURL += "&amount=\(((amount * 100) as NSDecimalNumber).intValue)" // The amount in cents without any decimal digits.

        if let unwrappedReference = reference, unwrappedReference != "" {
            capturePreauthActionURL += "&referenceNumber=\(unwrappedReference)" // transaction reference number

        if let unwrappedOrderCode = orderCode, unwrappedOrderCode != ""  {
            capturePreauthActionURL += "&orderCode=\(unwrappedOrderCode)" // transaction order code

        if let unwrappedShortOrderCode = shortOrderCode, unwrappedShortOrderCode != ""  {
            capturePreauthActionURL += "&shortOrderCode=\(unwrappedShortOrderCode)" // transaction short Order Code

        if let dateFrom = dateFrom {
            capturePreauthActionURL += "&txnDateFrom=\(dateFrom)"

        if let dateTo = dateTo {
            capturePreauthActionURL += "&txnDateTo=\(dateTo)"

        let showReceipt = UserDefaults.standard.value(forKey: "show_receipt") as? Bool ?? true
        capturePreauthActionURL += "&show_receipt=\(showReceipt)"

        let showResult = UserDefaults.standard.value(forKey: "show_transaction_result") as? Bool ?? true
        capturePreauthActionURL += "&show_transaction_result=\(showResult)"

        return capturePreauthActionURL
        let capturePreauthActionURL: String = createCapturePreauthRequest(captureAmount: 5, reference: nil, orderCode: nil, shortOrderCode: "1091139195",, dateFrom: "2021-03-29T00:00:00.000+0300", dateTo: nil)
        (UIApplication.shared.delegate as? AppDelegate)?.performInterAppRequest(request: capturePreauthActionURL)

Request example


Capture Pre-auth response

After executing a Capture Pre-auth transaction, the ‘ | Terminal’ application responds with a result to indicate if the transaction has been approved or not.

The result is received as a URI in the callback activity.

The table below summarises the contents of an approved response.

Field Description Example
callback The URI callback that will handle the result. 'interapp-callback://result'
status The status of the transaction. 'success'
message A string containing information about the transaction status. 'Transaction successful'
action Capture Pre-auth transaction. 'capture_pre_auth'
clientTransactionId The client transaction ID. '12345678901234567890123456789012'
amount The amount in cents without any decimal digits. '1200' = 12 euro
cardType The card type. 'Debit Mastercard'
accountNumber The card number masked. Note that only the 6 first and the 4 last digits are provided. All other digits are masked with stars. '537489******1831'
orderCode The order code. '1091166300000136'
shortOrderCode The order code in short format. '1091166300'
tid A 12 character string indicating the terminal's TID number. '16016684'
transactionDate The transaction date in ISO 8601 format. '2019-09-13T12:14:19.8703452+03:00'
transactionId A unique identifier for the transaction. 'a78e045c-49c3-4743-9071-f1e0ed71810c'


A Capture Pre-auth response result for an approved transaction looks as follows:

It is expected that certain transactions will fail for various reasons. A Capture Pre-auth response result for a failed transaction looks as follows:

The structure of the message is the same as in the case of an approved transaction.

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