Payment Request

A payment request starts a payment on the terminal. The shopper taps or inserts their card, and you get the result back in the same call.

Flow

1. Your POS sends a payment request to Adyen.
2. Adyen forwards it to the terminal, which asks the shopper for their card.
3. The terminal processes the payment.
4. Your POS gets the result in the response.

Test URL

POST https://terminal-api-test.adyen.com/sync

Add your API key to the header:

• X-API-Key: [your-api-key]

warning

The connection stays open until the shopper finishes. Set your HTTP timeout to at least 150 seconds.

Request Example

{
  "SaleToPOIRequest": {
    "MessageHeader": {
      "ProtocolVersion": "3.0",
      "MessageClass": "Service",
      "MessageCategory": "Payment",
      "MessageType": "Request",
      "SaleID": "POS-01",
      "ServiceID": "0001",
      "POIID": "S1F2-000158213601234"
    },
    "PaymentRequest": {
      "SaleData": {
        "SaleTransactionID": {
          "TransactionID": "9990QQAZ1221",
          "TimeStamp": "2026-10-01T12:00:00+00:00"
        }
      },
      "PaymentTransaction": {
        "AmountsReq": {
          "Currency": "ISK",
          "RequestedAmount": 4890
        }
      }
    }
  }
}

Request Fields

Field	Type	Required	Description	Example
MessageCategory	String	Required	The type of request. Payment for a payment.	Payment
SaleID	String	Required	The ID of your POS system or cash register.	POS-01
ServiceID	String	Required	Your unique ID for this request. Must be unique per terminal within 48 hours. Max 10 characters.	0001
POIID	String	Required	The ID of the terminal. See Get Started.	S1F2-000158213601234
TransactionID	String	Required	Your reference for the payment.	9990QQAZ1221
TimeStamp	String	Required	The date and time of the request, in ISO 8601 format.	2026-10-01T12:00:00+00:00
Currency	String	Required	The three-character ISO currency code.	ISK
RequestedAmount	Decimal	Required	The amount in major units, so 4890 is 4.890 ISK and 10.99 is 10,99 EUR.	4890

caution

RequestedAmount is in major units. This differs from Straumur's Hosted Checkout and Payment Gateway, which use minor units.

Response

{
  "SaleToPOIResponse": {
    "MessageHeader": {
      "MessageCategory": "Payment",
      "MessageType": "Response",
      "SaleID": "POS-01",
      "ServiceID": "0001",
      "POIID": "S1F2-000158213601234"
    },
    "PaymentResponse": {
      "POIData": {
        "POITransactionID": {
          "TransactionID": "BV0q001765198762003.NC6HT9CRT65ZGN82",
          "TimeStamp": "2026-10-01T12:00:15.000Z"
        }
      },
      "PaymentResult": {
        "AmountsResp": {
          "Currency": "ISK",
          "AuthorizedAmount": 4890
        }
      },
      "Response": {
        "Result": "Success",
        "AdditionalResponse": "pspReference=NC6HT9CRT65ZGN82&..."
      }
    }
  }
}

Response Fields

Field	Type	Description	Example
Result	String	Success or Failure.	Success
ErrorCondition	String	Only on failure. Why the payment failed, for example Refusal or Aborted.	Refusal
TransactionID (in POIData)	String	The terminal's transaction reference. You need it for refunds. The part after the dot is the PSP reference.	BV0q001765198762003.NC6HT9CRT65ZGN82
AuthorizedAmount	Decimal	The amount that was authorized.	4890
AdditionalResponse	String	Extra details about the payment, as URL-encoded key-value pairs.	pspReference=NC6HT9CRT65ZGN82&...

tip

If you don't get a response (for example a timeout), don't send the payment again. Check what happened with a Transaction Status request.