> ## 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.

# detectAndAuth

> Detect, read, and pre-authorize funds in a single-phase operation.

The `detectAndAuth` method combines card detection and pre-authorization into a single command. It is the primary method used for Pay-at-the-Pump transactions, streamlining the workflow by activating the reader and requesting a financial hold in one step.

Use this method to:

* Simultaneously activate the reader and prepare the authorization request to reduce total transaction time.
* Reserve funds immediately upon card tap, dip, or swipe to allow for instant pump activation.
* Minimize the logic required between card detection and authorization by handling both through a unified command.

## Requests

All requests must include the `command`, `requestId`, and the `amount` to be held. The terminal will remain in a "Waiting for Card" state until a payment method is presented or a timeout occurs.

The following example shows a typical request:

```json theme={null}
{
"command": "detectAndAuth",
"requestId": "req-1-3",
"data": {
"amount": 50000,
"tranType": 1,
"channels": ["CTLS", "CHIP", "SWIPE"]
}
}
```

### Parameter Definitions

The table below describes the parameters available for this request:

| Name         | Type    | Required | Description                                                                                                                          |
| :----------- | :------ | :------- | :----------------------------------------------------------------------------------------------------------------------------------- |
| **amount**   | integer | Yes      | The amount to hold/pre-authorize in minor units (refer to `decimalPlace`).                                                           |
| **tranType** | integer | No       | `1`: Pre-authorization, `2`: Pre-selection (Default is `1`).                                                                         |
| **channels** | array   | No       | Defines allowed payment methods: `CTLS` (Contactless), `CHIP` (EMV), `SWIPE` (Magnetic Stripe), or `QR`. Defaults to all if omitted. |

## Responses

The terminal returns a response only after the card has been successfully read and the authorization has been processed by the payment gateway.

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

```json theme={null}
{
"requestId": "req-1-3",
"data": {
"transactionId": "TXN-20260113-003000",
"authorizedAmount": 50000,
"state": "AUTHORIZED",
"cardBrand": "MASTERCARD",
"cardEntryMode": "CHIP",
"maskedPan": "************5678",
"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"
}
}
```

<Info>
  **Note:** If a QR code is used, the client system is responsible for any external authorization and settlement logic.
</Info>

### Response Parameters

Below are the parameters returned in the `data` object upon a successful transaction:

| Name                 | Type    | Description                                                                                 |
| :------------------- | :------ | :------------------------------------------------------------------------------------------ |
| **transactionId**    | string  | The unique ID for the authorized transaction. **Save this value** for the `settle` command. |
| **authorizedAmount** | integer | The final amount approved and held by the bank.                                             |
| **state**            | string  | Returns `AUTHORIZED` upon success.                                                          |
| **cardBrand**        | string  | The brand of the detected card (e.g., MASTERCARD).                                          |
| **cardEntryMode**    | string  | The method used to capture data: `CTLS`, `CHIP`, `SWIPE`, or `QR`.                          |
| **maskedPan**        | string  | The masked card number for receipt and logging purposes.                                    |
| **aid**              | string  | The Application Identifier for EMV-based transactions.                                      |