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Point of Sale Integration

Getting started with POS integration

PPaaS is designed to be integrated with various Point of Sale (POS) configurations.

A POS can use PPaaS for many functions including:

  • Integrating a payment functionality (see the Retail APIs described below),
  • Displaying a transaction list or to retrieve transaction information such as a transaction receipt to be printed by the ECR

For this PPaaS integration, the software running on the POS can be integrated with PPaaS by:

  • Directly calling the PPaaS Cloud APIs to access to different PPaaS features.
  • Using libraries from the Endpoint SDK that ease such integration.

Retail APIs

For a POS software to interface with a payment device and execute payment within a payment device, PPaaS provides the PPaaS Retail APIs. The PPaaS Retail APIs implement the Nexo Retailer protocol v5 international standard (https://www.nexo-standards.org/standards/nexo-retailer-protocol) with JSON message format. PPaaS Retail APIs are cloud-based APIs, which provide the following benefits:

  • Seamless integration with Cloud-based POS solutions
  • Easier communication between POS and payment devices compared to local connectivity (for example, wired connectivity)
  • Enabling flexible configuration of POS and payment devices accross the store. This provides the ability to have a tablet acting as a POS, from which a staff selects the payment device to use for the payment process.

Supported functionality

The Retail APIs allows to send requests to a payment device as shown in the block diagram:

The list of functionalities supported by the latest version of the Retail APIs is:

  • Listing available payment devices in the store where the POS is registered along with the list of supported payment methods
  • Managing a session from a POS to a payment device within a merchant store
  • Triggering sale transactions with an amount and a payment method

The Retail APIs are able to work with any number of payment devices registered in PPaaS as long as the payment device is compatible with PPaaS, i.e. having a payment device with a payment application supporting with the Retail APIs.

Retail API Integration

The sequence diagram describes a typical Cloud Retail API interaction between the POS, PPaaS, and the payment device.

For security reasons, for each merchant store, it is required to have the POS registered into PPaaS. This step has to be performed directly by the merchant in the PPaaS portal for each of its stores. The registration process will assign a unique application ID and secret per POS. This value pair must be configured in the POS solution that will authorize the POS to trigger requests to payment device located in the same store (via the getToken API). This mechanism allows only a legitimate POS to send requests to a payment device in a given store. It also allows to easily deregister a POS in a given store without an impact to any other POS in the same store or elsewhere.

It is the responsibility of the POS software provider to properly secure the application secret.

In the case of the all-in-one configuration, a payment device runs both the payment application and the POS software. In this case, the security is managed the same way as for any other PPaaS services accessed within a payment device, i.e. via Mutual Transport Layer Security (mTLS).

Payment devices integrated with Retail APIs can still be used standalone with the POS.


  • POS software must have an Internet connection
  • Use of the Retail APIs requires the PPaaS Client to have subscribed to the Retail APIs PPaaS service.
  • The payment device and the POS are registered into PPaaS.
  • The software within the payment device is compatible with the Retail APIs.

How to get started with Retail APIs

How to register a POS with PPaaS

Although it is generally the role of the merchant to register the POS, for development purpose, you need to register at least one POS into the system. Once a POS is registered, an Application ID and Key are auto created for the respective POS.

To add a POS to a store:

  1. From the STORES tab select the new store that you created or select a store for which you want to attach a POS.

  2. Navigate to the POINTS OF SALE tab, click ADD POINT OF SALE.

  3. On the New point of sale drawer, enter the Name and Reference fields.

  4. Click SAVE. The Point-of-sale information is now added to the list. Also displays the Application ID and Key.

  5. Use the Application ID and Key details corresponding to the POS to set-up the POS.

  • To copy the Application ID, click the copy icon.
  • To copy the Key, click the copy icon.
  • To view the displayed key for the corresponding POS, click the view icon.