Alongside the three primary integration methods (Local API, Cloud API, App-to-App), Market Pay terminals interoperate with several market-specific protocols. This page explains what they are, how they are supported, and links to each one.
At onboarding, you can select the protocol you want your integration to be in.
What a market-specific protocol is
A market-specific protocol is an external integration that Market Pay does not own. It defines how a POS or cash register talks to a payment terminal and can cover specific regions (France, Italy…) or device class (unattended, vending). Some POS vendors, operating in those markets have an already compatible solution to connect "plug and play" to the terminal.
Support matrix: connectivity & setup
| Concert | Protocollo 17 | LTI | MDB | |
|---|---|---|---|---|
| Market / use | France | Italy | Wallee | Unattended / vending |
| Transport | TCP/IP, custom TLV | TCP (integrated) | TCP, length-framed | MDB v4.3 physical bus |
| Pre-requisites | Marketpay Master installed | Marketpay Master installed | Marketpay Master installed | MDB Slave app |
Concert (Protocole Caisse)
The Concert protocol (CAISSE-AP V3.20), also called Protocole Caisse, is a common French cash-register protocol governed by the Association du Paiement. On Market Pay terminals it runs over TCP/IP using a custom 2-byte length prefix plus TLV payload.
Supported operations
| Concert operation (CD tag) | Supported |
|---|---|
Débit — Achat (0) |
Yes |
Crédit — Remboursement (1) |
Yes |
Annulation (2) |
Yes |
Duplicata (3) |
Yes |
PreAuto (4) |
Yes |
Valid PreAuto (5) |
Yes |
Annul PreAuto (6) |
Yes |
Télécollecte (B) |
Yes |
Identification (I) |
Yes |
Affichage d'un menu (C) |
No |
Affichage d'une question (D) |
No |
Impression buffer (P) |
No |
Note
Menu display, question display, and print-buffer operations are not mapped. Do not build a Concert integration that depends on the terminal handling these — they will not reach a Retailer operation.
Protocollo 17 (ECR17)
Protocollo 17 (P17 / ECR17) is the common ECR protocol used on the Italian market. On Market Pay terminals it is available in integrated mode only (standalone terminals are out of scope).
Supported operations
The message set follows the Protocollo 17 specification and maps to the equivalent Nexo Retailer operations (payment, reversal, and the standard Italian-market flows). For the authoritative message-level contract, use the Nexi specification below; use this page for terminal-side configuration only.
| LTI message | Supported |
|---|---|
| Terminal status | Yes |
| Payment | Yes |
| Payment with Extended Result | Partial |
| Reversal |
|
| Pre-Authorization Request | 26.09 |
| Incremental Authorization | 26.09 |
| Pre-Authorization Closure | 26.09 |
| Card verification | 26.09 |
| Close session | |
| Terminal totals | 26.09 |
| Send last result | Yes |
| Enable and disable printing receipt on ECR | No |
| Send ticket | No |
| Reprint ticket | No |
Tip
The external Protocollo 17 documentation is maintained by Nexi at the Nexi Developer Portal.
LTI
LTI is a lightweight TCP-based protocol used to integrate loyalty and ticketing systems, and is used in the PayWorld project to preserve backward compatibility during migration. It is available in integrated or unattended mode. Configuration adds a dedicated LTI IntegratedApplication entry with a TCP socket interceptor.
Supported operations
| LTI message | Supported |
|---|---|
| FinancialTrx | Yes |
| Reversal | Yes |
| AbortCardEntryNotification | Yes |
| Activation | Yes |
| SiConfig | Yes |
| PinpadInformation | Yes |
| DisplayNotification | Yes |
| Ping | Yes |
| ErrorNotification | Yes |
| PrinterNotification | Yes |
Note
A payment produces two outbound LTI messages: the financial response and a separate PrinterNotification carrying the raw receipt buffer. Handle both.
The external LTI specification is published by Wallee.
MDB (unattended)
MDB (Multi-Drop Bus) is the common protocol for unattended / vending deployments, where the terminal operates as a cashless payment device connected to a Vending Machine Controller (VMC) over MDB v4.3. On Market Pay it is implemented as an MDB Slave application whose parameters are managed per-group in NTMS rather than via integrated_apps_config.xml. Primary hardware is the IM30, which has a physical MDB Slave port. Command levels L1–L3 (including multivend) are auto-negotiated with the VMC at connection.
Supported operations
MDB is a device-bus protocol, not an ECR message set — support is expressed as MDB command levels (L1–L3), negotiated with the VMC rather than mapped to individual Retailer operations. Because the integration is not yet live, treat the level coverage as provisional until release.