### Event Type
- **Type**: `const`
- **Enum**: Required
- **Description**: Event type
  - Allowed: `card_authorization.challenge_response`

### Event Token
- **Type**: `uuid`
- **Required**: Yes
- **Description**: Globally unique identifier for the event

### Transaction Token
- **Type**: `uuid | null`
- **Required**: Yes
- **Description**: The token of the transaction associated with the authorization event being challenged

### Card Token
- **Type**: `uuid | null`
- **Required**: Yes
- **Description**: The token of the card associated with the challenge

### Challenge Method
- **Type**: `string`
- **Enum**: Required
  - Allowed: `SMS`, `OUT_OF_BAND`

### Response
- **Type**: `string`
- **Enum**: Required
  - Allowed: `APPROVE`, `DECLINE`

### Created
- **Type**: `date-time`
- **Required**: Yes
- **Description**: The timestamp of when the challenge was created

### Completed
- **Type**: `date-time | null`
- **Required**: Yes
- **Description**: The timestamp of when the challenge was completed

### Status Code
- `200`: Return a 200 status to indicate that the data was received successfully

### Example JSON
```json
{
  "event_type": "card_authorization.challenge_response",
  "event_token": "00000000-0000-0000-0000-000000000001",
  "transaction_token": "00000000-0000-0000-0000-000000000002",
  "card_token": "00000000-0000-0000-0000-000000000003",
  "challenge_method": "SMS",
  "response": "APPROVE",
  "created": "2025-07-17T07:07:29Z",
  "completed": "2025-07-17T07:08:15Z"
}
```