Merchant Quick Start PISP Initiation

Quick Start - Let's make an Open Banking payment!

Overview

This section gives merchants an overview of the API calls required for the three integration models:

CHECKOUT
SELF-HOSTED
SELF-HOSTED-CALLBACK
REDIRECT

See PISP Implementation Options for more on these options.

Depending on the setup that best suits your business needs, the API calls that you need to make and how you process the responses vary.

A Note on Authentication

When interacting with the Nuapay Endpoints you must be authenticated via one of the following:

API Keys
OAuth Tokens

For more details, and to decide on the approach that suits your business needs, see API Key Authentication and Token Authentication.

Postman Collection

We highly recommend that you use Postman to test our PISP APIs on the Sandbox environment. Download it for free from www.postman.com/downloads.

Tip: Unlike the Swagger specification, the Postman Collection we’ve created allows you to work with the APIs directly in our Sandbox environment. While our Swagger file is a formal definition of our PISP service, which you can use to generate client libraries, the Postman Collection logically groups the services together so that you can see the business logic of why (and when) to call the various PISP endpoints.

You will need to download:

A Collection .JSON file.
An Environment .JSON file.

Download the files from Github here: Postman Collections on Github

If you are new to Postman and are unsure how to import the collection, please see the README.

Once you have donwloaded the Collection and the Environment files:

Open Postman.
Import the collection files.
Specify your API Key.

Tip: If you don’t already have one, contact our Support Team to request an API Key: api.support@nuapay.com.

Checkout Mode

Note: CHECKOUT and REDIRECT is only available for merchants who want to process GBP payments; if you want to process EUR transactions then you must go with either the SELF-HOSTED or SELF-HOSTED-CALLBACK integration.

Call the following services in this order:

POST	Access Token	(Optional) Use this service to retrieve an OAuth token, which you will use to authenticate yourself in subsequent calls. Alternatively you may use your API Key.
POST	Create Payment	The Create Payment service generates an Open Banking payment object, returning a unique `userInterfacepaymentId` with an (initial) status of `PENDING`. Apply the Nuapay-provided JS and CSS on your page to render the Bank Selection screen for your payers.
-	-	The PSU selects a bank (also referred to as the ASPSP) and is redirected to authenticate and approve the payment on that ASPSP’s online banking portal.
GET	Retrieve Payment Status	Retrieve the status of the payment

For more details on this see the Merchant-level Checkout Setup.

Self-Hosted

Call the following services in this order:

POST	Access Token	(Optional) Use this service to retrieve an OAuth token, which you will use to authenticate yourself in subsequent calls. Alternatively you may use your API Key.
GET	Retrieve Banks	Use this service to give your PSU a list of banks from which to choose
-	-	The PSU selects a bank (also referred to as the ASPSP).
POST	Create Payment	Once the user selects an ASPSP, pass its `bankId` in the payment request.
-	-	The PSU is redirected to authenticate and approve the payment on that ASPSP’s online banking portal. Once the user approves or declines the payment he/she is redirected to the `merchantPostAuthUrl` (as referenced in the Create Payment call).
GET	Retrieve Payment Status	Retrieve the status of the payment.

For more details on this see the Merchant-Level Self-Hosted Setup

Self-Hosted Callback

Call the following services in this order:

POST	Access Token	Use this service to retrieve an OAuth token, which you will use to authenticate yourself in subsequent calls.
GET	Retrieve Banks	Use this service to give your PSU a list of banks from which to choose
-	-	The PSU selects a bank (also referred to as the ASPSP).
POST	Create Payment	Once the user selects an ASPSP, pass its `bankId` in the payment request.
-	-	The PSU is redirected to authenticate and approve the payment on that ASPSP’s online banking portal. Once the user approves or declines the payment he/she is redirected to the `merchantPostAuthUrl` (as referenced in the Create Payment call).
POST	Access Token	Pass your merchant API Key with the required scope = `openbanking_callback` to retrieve an OAuth access token.
POST	Forward Payment Callback	In this mode as the callback/redirect from the ASPSP does not go directly to the Nuapay TPP, it is required to forward the details via this service; you must pass your `callbackAccessToken` and the `callbackParams`
GET	Retrieve Payment Status	Retrieve the status of the payment.

For more details, see Merchant Self-Hosted-Callback Payment Page Setup.

Redirect Mode

Call the following services in this order

POST	Access Token	(Optional) Use this service to retrieve an OAuth token, which you will use to authenticate yourself in subsequent calls. Alternatively you may use your API Key.
POST	Create Payment	The `integrationType` must be set to REDIRECT and the `merchantPostAuthUrl` must be provided. The Create Payment service generates an Open Banking payment object, returning a unique `userInterfacePaymentId` with the payment object having an initial status of `PENDING`. The URI must be passed to the PSU; once the user clicks the link the Bank Selection screen is launched in a new browser window/tab.
-	-	The PSU selects a bank and is redirected to authenticate and approve the payment on that ASPSP’s online banking portal.
GET	Retrieve Payment Status	Retrieve the status of the payment.

For more details on this see the Merchant-level Redirect Setup.