Request and Response Format - Nayax Developer Portal

The Marshall Pro protocol uses a unified JSON structure for every message. This consistency allows you to build a single “wrapper” in your code to handle all terminal communications.

Request Object

Every command sent from your system to the VPOS must follow this structure:

Field	Type	Required	Description
command	`string`	Yes	The name of the API method (e.g., `"status"`, `"pay"`).
requestId	`string`	Yes	A unique ID used to track the response.
data	`object`	No	A container for the specific parameters of the command.

Request Example

{
  "command": "<command_name>",
  "requestId": "<unique_request_id>",
  "data": {
    "param1": "value1",
    "param2": "value2"
  }
}

Response Object

The terminal’s response always mirrors your requestId so your system knows exactly which command is being answered.

Success Response

If the command is processed successfully, the terminal returns the requested information inside the data object.

{
  "requestId": "<request_id_echo>",
  "data": {
    "status": "success",
    "details": "..."
  }
}

Error Response

If an issue occurs, the response will include an error code and a descriptive message.

{
  "requestId": "<request_id_echo>",
  "errorCode": 400,
  "errorMessage": "Invalid command parameters"
}