nexo FAST Specification

nexo FAST Specification

implementing nexo FAST will reduce development and certification costs for terminal manufacturers, merchants and bankS
nexo FAST is based on EMV Chip and PIN technology and describes unambiguously the financial application on a terminal which is compliant to the SEPA Cards Framework (SCF) of the European Payments Council (EPC) and also meets the functional requirements in the SEPA Cards Standardisation Volume Book of Requirements. nexo FAST has been developed with the objective of:
  • Supporting a uniform "look and feel" of transactions from the cardholder’s perspective
  • Reducing the risks of interoperability obstacles between applications
  • Enabling an open market for EMV-based components
  • Serving as the basis for a "one-stop shopping" for terminal testing and mutual recognition of type approval
  • Describing unambiguously the financial application on the SCF compliant terminal
The nexo FAST architecture and interfaces are defined on a logical level. Do not require a specific hardware or software architecture. It also Introduce the major concepts of interaction with the acquirer host, the sale system through: HAP -The interface to the Host Acquirer Protocol application and SCAP - The interface to the Sale System, Cardholder and Attendant Protocol application.
The nexo FAST application internal structure main functional blocks are: Terminal and Card Service Initiation; Card Service Processing and; Card Interaction Layer including Kernel processing.

nexo FAST describes a financial application on the Point of Interaction (POI) terminal based on EMV chip and PIN technology and includes the following topics:

1) The specification of a terminal transaction flow for the terminal-to-card interface, the terminal-to-cardholder interface and the exception handling. Defines the functionalities and identifies the minimum requirements to be supported for the following Card Services:

Payment Service (attended and unattended). This is the basic Card Service on the terminal and performs a transaction that generates all necessary data for authorisation, clearing, and settlement required to pay for the purchase of goods, services, etc. The following options are also covered:

  • Increased Amount. This option allows the customer to increase the amount paid by adding an extra amount e.g. a gratuity. It is usually supported only on attended terminals in some specific sectors.
  • Cashback. This option extends the Payment to include the delivery of cash. An extra amount is added to the total amount of a Payment. The customer receives this extra amount in cash along with the goods/services. For this option specific acceptance rules exist and it impacts the process at the terminal.

Refund Service (only attended). This is a Service which allows the merchant to reimburse the cardholder, e.g. when the cardholder returns goods to a merchant. However, Refund is not necessarily related to any transaction performed at the terminal where the Refund is performed.

Cancellation Service (only attended). This is a Service which occurs when a previously performed transaction is cancelled by the attendant. This may be restricted to the last transaction processed at the terminal or may be extended to any transaction not yet cleared to the issuer. The Cancellation Service may also be known as "Manual Reversal".

Pre-Authorisation Services (attended and unattended). These are Services used mainly but not only in the hotel and car rental businesses to fulfil the business requirements related to the fact that services are rendered in several steps. The first step is Pre-Authorisation which is used to secure an amount for a specific period of time. During the authorisation, the amount is only secured since neither the final amount nor the final date and time of the actual payment are known. Subsequent steps of this Service may be Update Pre-Authorisation and Payment Completion.

Cash Advance (only attended). This is a Service which allows the cardholder to withdraw cash at a merchant POS terminal or a bank counter.

Deferred Payment (attended and unattended). This is a Service which, together with the Deferred Payment Completion, enables the card acceptor to perform an authorisation for a temporary amount and a completion for the final amount within a limited time frame.

2) The following terminal environments:
  • Online only,
  • Offline with online capabilities,
  • Offline only.
  • The interface to any Host Acquirer Protocol application (HAP) which implements an SCS Volume compliant authorisation and clearing protocol
  • The interface to any Sale System, Cardholder and Attendant Protocol application (SCAP).
  • The data elements used to parameterise a nexo-FAST implementation.
  • The data elements used to perform a transaction with a nexo-FAST implementation.



nexo FAST is not intended to challenge or reassess the EMV specification, but to propose a common implementation of this specification and to add SEPA specific aspects to it.

The benefits of adopting nexo FAST are multiple:
  • EMV compliancy: a terminal running a nexo FAST application will be able to accept all payment cards, provided they are compliant with EMV specifications.


  • Protocol agnostic: nexo FAST has been designed in a way it could work with different acquirer, TMS or retailer protocols. It can therefore easily be integrated with any of those protocols, so as to match market needs.
  • Multi-acquirer: nexo FAST has been designed since its inception as a multi-acquirer payment application.


  • Security: the specifications are based on state-of-the-art security. A strong emphasis has been made on how the terminal data are stored and accessed, to ensure that each module within the nexo FAST application can only access the data that are strictly necessary to its task.

​Overall, implementing nexo FAST will reduce development and certification costs for terminal manufacturers, merchants and banks.

nexo FAST Specifications