> ## Documentation Index
> Fetch the complete documentation index at: https://nayax-44d6e37b-docs-marshall-faq-redistribution.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# cardDetect

> Enable the reader to detect and read payment methods without immediate authorization.

The `cardDetect` method activates the terminal's reader to identify and capture data from a payment method (Card or QR) without initiating a financial hold or charge. It serves as a versatile tool for workflows where customer identification must precede the payment phase.

Use this method to:

* Recognize customers via loyalty cards or mobile QR codes to apply personalized discounts.
* Retrieve masked card data to welcome returning users or verify membership status.
* Use card data to determine eligible fuel types or promotions before requesting authorization.
* Accept Contactless (CTLS), Chip (EMV), Magnetic Stripe (Swipe), and QR code scanning.

Example of the card detection prompt on a Nayax device:

<img src="https://mintcdn.com/nayax-44d6e37b-docs-marshall-faq-redistribution/97AxTUwdTqLzbB-t/images/approved.png?fit=max&auto=format&n=97AxTUwdTqLzbB-t&q=85&s=b2733276c9460a158fd255ade1030663" alt="cardDetect" width="288" height="512" data-path="images/approved.png" />

## Requests

All requests must include the `command` and a unique `requestId`. While this method does not authorize funds, an `amount` must be provided for display purposes on the terminal screen.

The following example shows a typical request:

```json theme={null}
{
"command": "cardDetect",
"requestId": "req-005",
"data": {
"amount": 50000,
"tranType": 1,
"channels": ["CTLS", "CHIP", "SWIPE"]
}
}
```

### Parameter Definitions

The table below describes the parameters available for the detection request:

| Name              | Type    | Required | Description                                                                                    |
| :---------------- | :------ | :------- | :--------------------------------------------------------------------------------------------- |
| **amount**        | integer | Yes      | The amount to display on the screen during detection (refer to `decimalPlace`).                |
| **tranType**      | integer | No       | `1`: Pre-authorization, `2`: Pre-selection (Default is `1`).                                   |
| **channels**      | array   | No       | Defines allowed payment methods: `CTLS`, `CHIP`, `SWIPE`, or `QR`. Defaults to all if omitted. |
| **buttonMediaId** | string  | No       | Optional button displayed below the channels image. Currently supported value: `useQR`.        |

## Responses

The VPOS terminal returns a response once the user interacts with the reader or a QR code is successfully scanned.

The following example shows a typical **credit card** response:

```json theme={null}
{
"requestId": "req-005",
"data": {
"state": "CARD_READ",
"cardBrand": "VISA",
"cardEntryMode": "CTLS",
"maskedPan": "************1234",
"aid": "A0000000031010"
}
}
```

The following example shows a typical **QR code** response:

```json theme={null}
{
"requestId": "req-005",
"data": {
"state": "CARD_READ",
"cardEntryMode": "QR",
"qrCode": "1168743871706458"
}
}
```

The following example shows a **button press** response:

```json theme={null}
{
"requestId": "req-005",
"data": {
"state": "BUTTON_PRESS"
}
}
```

<Info>
  **Note:** When using `cardDetect` for non-credit card methods (such as proprietary QR codes) or when a button is pressed, the client system is responsible for any subsequent authorization or settlement logic. The reader is automatically disabled after a QR code scan or button press.
</Info>

### Response Parameters

The response data is categorized by the entry mode used by the customer:

| Name              | Type   | Description                                                                                             |
| :---------------- | :----- | :------------------------------------------------------------------------------------------------------ |
| **state**         | string | `CARD_READ` upon a successful card or QR detection; `BUTTON_PRESS` when the optional button is pressed. |
| **cardEntryMode** | string | The method used to capture the data: `CTLS`, `CHIP`, `SWIPE`, or `QR`. Not present for `BUTTON_PRESS`.  |
| **cardBrand**     | string | The brand of the detected card (e.g., VISA, MASTERCARD).                                                |
| **maskedPan**     | string | The masked Primary Account Number for identification purposes.                                          |
| **aid**           | string | The Application Identifier for EMV-based transactions.                                                  |
| **qrCode**        | string | The raw data string captured from a scanned QR code.                                                    |