Cloud ECR

We recommend that you use local communication protocols such as LAN or RS232 to connect to Wonder Terminals. This connection method is usually more stable and faster than an internet connection. However, we understand that in certain scenarios (e.g., when Wonder Terminals cannot be placed on the same network as your POS devices due to specific reasons), an internet connection may be the only option. Therefore, we have also prepared a connection solution based on internet technologies.

warning

Since the ECR itself already has a complete data encryption process, the Cloud ECR API does not require signature verification with an appid, unlike other Open APIs. This is to maintain consistency with the LAN/RS232 mode, so there is no need to refer to the authentication documentation.

Workflow

• Get the 6 digits numbers from wonder terminal paring page.
• Get terminal basic information via Get Device Info API.
• Send command to terminal via Send Command to terminal API, follow ECR body protocols

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• Use the 6 digits number to encrypt the Get Device Info API and Pair command.
• The Pair command will be return a new pin code, use the new pin code to encrypt other commands.

Environments

Please check Environments learn how to connect Sandbox or Production.

Data Format

Request body

Variable	Type	Required	Description
version	String	Y	Current communication protocol version number
action	enum	Y	Actions: Pair, DeviceInfo, Sale, ...
data	String	Y	Encrypted data, It is necessary to distinguish the encryption keys of this data: pinCode1 and pinCode2

Response body

Variable	Type	Required	Description
code	Number	Y	Current communication protocol version number
message	String	Y	Actions: Pair, DeviceInfo, Sale, ...
data	Object	Y	This data object is an ECR response data structure
data.version	String	Y	Please refer to the version description of the ECR response data structure
data.action	enum	Y	Please refer to the action description of the ECR response data structure
data.data	String	Y	Please refer to the data description of the ECR response data structure

Get Device info API

Retrieves the basic information of the device for subsequent operations.

• Device SN: Each command API request should include the device SN for backend identifier decide send command to which terminal.
• Local LAN Server Information: The terminal local network ECR API endpoint if it's connected a LAN network.

Request Body Header

Header Name	Comment
X-P-Business-ID	the business id
X-Request-ID	A unique UUIDv4 for track api call

Reqeust Body Format - Before encryption

Field Name	Comment
pairUuid	A randomly UUIDV4

{
  "header": {
    "requestID": "9c07d8d7-2a43-4a29-9c6d-6b8d8f7d44e5",
    "timestamp": "2025-11-12T10:12:04+00:00"
  },
  "body": {
    "pairUuid": "3f37e6c0-bf6e-4c00-b1fa-b2bd5e1d6a3b"
  }
}

Response - After decryption

Field Name	Comment
ip	The terminal local server IP Address
port	The terminal local server listen port
deviceSn	The terminal device SN

{
  "header": {
    "responseID": "2c7f32e1-b9e4-4b34-96cc-15c51289f69b",
    "clientDeviceSN": "NEXGO-N96-1170270945",
    "timestamp": "2025-11-12T10:12:04+00:00"
  },
  "body": {
    "ip": "127.0.0.1",
    "port": "4499",
    "deviceSn": "NEXGO-N96-1170270945"
  }
}

Use http://${ip}:${port}/v2/wonder/payment/ecr connect to Local ECR Server.

Send command to terminal API

Used to send commands to the terminal for execution. Check ECR interfaces get all command details.

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Note: Void/Refund commands will not be forwarded to the terminal and will be processed directly in the cloud. Therefore, Void/Refund operations do not depend on whether the device is powered on or the network is online.

Start building

Please refer to our Source Codes - Cloud ECR examples get more details.