# Post-authenticate

## Overview

The `postAuthenticate` method validates 3D Secure authentication results with the issuing bank. After the customer completes a challenge, this confirms the authentication was successful.

**Business Use Case:** After the customer returns from a 3DS challenge, validate the results before processing the payment to obtain liability shift.

## Purpose

| Scenario        | Action                               |
| --------------- | ------------------------------------ |
| After challenge | Validate the authentication response |
| Before payment  | Confirm authentication succeeded     |
| Liability shift | Obtain ECI/CAVV values               |

## Request Fields

| Field                | Type          | Required | Description                    |
| -------------------- | ------------- | -------- | ------------------------------ |
| `merchantOrderId`    | string        | Yes      | Your unique order reference    |
| `amount`             | Money         | Yes      | Transaction amount             |
| `paymentMethod`      | PaymentMethod | Yes      | Card details                   |
| `authenticationData` | object        | No       | 3DS result data from challenge |

## Response Fields

| Field                    | Type   | Description                     |
| ------------------------ | ------ | ------------------------------- |
| `connectorTransactionId` | string | Connector's authentication ID   |
| `status`                 | string | AUTHENTICATED, FAILED           |
| `authenticationData`     | object | Validated 3DS data (ECI, CAVV)  |
| `state`                  | object | State for payment authorization |
| `statusCode`             | number | HTTP status code                |

## Example

### SDK Setup

```javascript
const { PaymentMethodAuthenticationClient } = require('hyperswitch-prism');

const authClient = new PaymentMethodAuthenticationClient({
    connector: 'stripe',
    apiKey: 'YOUR_API_KEY',
    environment: 'SANDBOX'
});
```

### Request

```javascript
const request = {
    merchantOrderId: "order_001",
    amount: {
        minorAmount: 10000,
        currency: "USD"
    },
    paymentMethod: {
        card: {
            cardNumber: { value: "4242424242424242" },
            cardExpMonth: { value: "12" },
            cardExpYear: { value: "2027" }
        }
    },
    authenticationData: {
        eci: "05",
        cavv: "AAABBIIFmAAAAAAAAAAAAAAAAAA="
    }
};

const response = await authClient.postAuthenticate(request);
```

### Response

```javascript
{
    connectorTransactionId: "pi_3Oxxx...",
    status: "AUTHENTICATED",
    authenticationData: {
        eci: "05",
        cavv: "AAABBIIFmAAAAAAAAAAAAAAAAAA=",
        transStatus: "Y"
    },
    statusCode: 200
}
```

## Next Steps

* [Payment Service](https://docs.hyperswitch.io/integrations/prism/node/payment-service) - Authorize payment with 3DS data