Introduction

OLA stands for Open L2 API . It (OLA) is a programmable interface normalizing card processing (L2) services required by a payment application (L3).

Important: this interface has been designed from a Nexo Fast perspective. OLA is a global initiative aiming to cover a missing key element in the payment ecosystem: the EMV L2 API. However, OLA is generic enough to support any kind of payment dynamic beyond Nexo implementations.

Principles

Interacting with a L2 stack is based a simple principles:

1. Set pre-conditions

2. Initiate transaction

3. Eventually, complete transaction

4. Get post-conditions

Setting pre-conditionsconsists in pushing EMV parameters fecthed from a TMS to the L2 stacks. This step depends on the payment application implementation and the selection process that occurs during stage of the transaction.

Initiating and completing a transaction is about delegating the card processing to the L2 stack. It triggers a behavior that has been L2 certified and granted with a LoA. It is based on the configuration parameters previously pushed.

Getting post-conditionsconsists in gathering a series of information to be able to provide a final outcome for the transaction.

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• A payment application detects whether a contact or contactless application will be triggerred

• A payment application implements the logic to select a final application based on OLA services

• A payment application configures the EMV parameters based on the final selection

Architecture

OLA aims:

• To break dependencies between different integration levels and L2 implementations

• To fill the gap between different objectives of testability (usually dependent on the context of integration)

• To normalize L2 API beyond certificatibility objectives

The API

See Developer's Guide for more details on OLA API.

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