Introduction

The LAN integration lets software that runs on another machine — a Windows till, a kitchen display, a kiosk backend — send App2App requests to a POS+ device on the same local network. The device performs the payment and answers on the same connection.

It is the same request model as App2App: a JSON object with a header and a data part, the same operations and the same PP_A2A_* error codes. Only the transport differs: instead of an Android intent, the message travels as one line of JSON over TCP.

How it works

┌──────────────────┐  1. {"header":…,"data":…}\n   ┌──────────────┐
│                  │ ────────────────────────────▶ │              │
│  Your POS        │         TCP :8471             │  POS+ device │
│  software        │                               │              │
│                  │ ◀──────────────────────────── │  2. cashier  │
└──────────────────┘  3. one line of JSON\n        │     + card   │
                                                   └──────────────┘

1. Your software opens a TCP connection to the device (port 8471 by default) and writes a request as a single line ending with \n.
2. POS+ comes to the foreground and runs the operation: the customer taps the card, the cashier confirms cash, and so on.
3. When the receipt screen closes, the device writes the result as a single line on the same connection.

When to use LAN

LAN needs the internet only to validate your keys. The payment request itself does not leave the local network until POS+ talks to the bank.

Requirements

• A POS+ device on Android (SoftPOS is not supported) with Local communication turned on. See Connection.
• POS+ logged in on the device at least once.
• Your api_key and secret_key from the Credentials page of the developer portal. They are sent in every request header.
• Network access from your machine to the device on TCP 8471 (and UDP 8470 if you use discovery).

Next steps

• Connection — enabling the device, discovery, framing and authentication
• Commands — every transaction_type with request and response
• Errors — error codes, recovery and concurrency
• Reference — models and enums