Adding Open Banking (Redirect mode) as a payment option to your Payment Page requires a little configuration as outlined below. In Redirect mode you will use the Nuapay user interface for Bank Selection and Confirmation screens, with the screens being launched in a new browser window. Alternatively, you can use this mode if you would like to implement a setup where PSUs are emailed a link to the Bank Selection page or scan a QR code, for example.


Redirect mode allows merchants to:

  • Use the Nuapay User Interface for the bank selection and bank confirmation screens.
  • Offer a full browser window/tab for the PSU interaction (this is in contrast to CHECKOUT mode, where the bank selection and bank confirmation screens are rendered in a pop-up window).
  • Create a payment link which can be presented to the PSU.

Steps in the Redirect Flow

A detailed overview of the various steps involved in the REDIRECT flow is provided in the image below.

Redirect Flow - Partner
REDIRECT Flow - Partner

In Redirect mode you will:

  1. Use your partner-level API key to retrieve a token representing the required merchant. (For more on this see list organisations and retrieving tokens).
  2. Call the /payments endpoint (see Create Payment), on behalf of the merchant, using the OAuth token retrieved in the previous step.
  3. Set the integrationType to REDIRECT. You must also provide the merchantPostAuthUrl - this is mandatory for the Redirect flow.
  4. The TPP creates the payment object and returns the userInterfacePaymentId.
  5. The PSU then needs to be redirected to the URL with the userInterfacePaymentId. You must build a URI that can be used on a web page or sent by an e-mail to the end user. The URL will be similar to the following (on the Production environment):
  6. The end user clicks the link and the Nuapay TPP (with the Bank selection window) is displayed in a new browser window.
  7. When the user selects a bank he/she is redirected to the selected ASPSP to authorise the payment.
  8. The ASPSP redirects the PSU back to the TPP UI which processes that callback.
  9. The TPP UI then redirects the PSU to the merchantPostAuthUrl with the parameter paymentId.
  10. Use Retrieve Payment to determine the final payment status. (This integration also supports webhooks so you can be informed when the payment is completed).

Merchant Post-Auth URL Handling

The merchant merchantPostAuthUrl is sent as follows:

The payload of this request that you need to process includes:

Headers e.g. Content-Type: application/x-www-form-urlencoded
Body e.g. paymentId=4m6vjed32a&userInterfacePaymentId=95125314-5161-4769-926f-143ff6cbdd82

Please note that the ‘paymentId’ allows you to look up the payment associated with this callback.


An API Key or an OAuth token uniquely identifies you on Nuapay and is required to allow you to use our API services.

For more on API Keys and OAuth, see the API Basics section.

Calling the Payment Endpoint

The Open Banking payment endpoint returns a payment identifier on a successful invocation.

To generate a payment ID:

  1. Generate a server-to-server call to /payments.
  2. Ensure that you have referenced your API Key or OAuth token in the request.
  3. The /payments service is described in Create Payment.

Adding the CSS and JS File References

On your payment page you will need to add the following:

For Sandbox

<script src=""></script>

For Production

<script src=""></script>

Adding The Open Banking Pay Button

At this point you have:

  • Added the JS and CSS links to your payment page.
  • Retrieved the payment ID (via the Create Payment service).

To enable the PAY button you will need to add an onclick event. See the example below:

<a class="btn btn-primary" href="#" onclick="NuapayOpenBanking.redirect(uiid, tppUibaseUrl);">Pay Now</a>

This button will open the Select Banks on a new browser tab or window for the userInterfacePaymentId (the uiid).

If you have decided to email the link to the PSU or have provided a QR code, that user may begin the payment, drop out of the flow and retry accessing the link later. In that case:

  • The TPP will check the existing payment status in the TPP database.
  • If the payment’s current status means that the payment cannot proceed (e.g. if the payment is in SETTLEMENT_REJECTED) an alert is displayed to the user on the TPP and he/she cannot continue.
  • If the payment is in status PENDING then the user will be able to proceed and complete the payment. Note that PENDING is the only status that will allow the PSU to proceed.