> ## Documentation Index
> Fetch the complete documentation index at: https://beta-developers.mizaniyapay.dz/llms.txt
> Use this file to discover all available pages before exploring further.

# VTPE Product Information API Error Responses

> Your Product Information API must return NOT_FOUND, ALREADY_PAID, and SERVICE_UNAVAILABLE errors to VTPE with the correct HTTP status and JSON format.

When VTPE calls your Product Information API (`GET {API_URL}/{reference}`), return the appropriate error code so VTPE can inform the customer about what went wrong. This page documents the three required error responses.

## Error Response Format

All error responses from your Product Information API must use this JSON structure:

```json theme={null}
{
  "error": "CODE",
  "errorMessage": "Human-readable message"
}
```

The `error` field is the machine-readable code that VTPE uses to determine the error type. The `errorMessage` field is displayed to the customer.

## Error Codes

### NOT\_FOUND (404)

Return this error when the requested reference does not exist in your system.

| Property    | Value      |
| ----------- | ---------- |
| HTTP Status | 404        |
| Error Code  | NOT\_FOUND |

```json theme={null}
{
  "error": "NOT_FOUND",
  "errorMessage": "Reference not found"
}
```

### ALREADY\_PAID (409)

Return this error when payment was already completed for this reference. This prevents the customer from paying twice for the same order.

| Property    | Value         |
| ----------- | ------------- |
| HTTP Status | 409           |
| Error Code  | ALREADY\_PAID |

```json theme={null}
{
  "error": "ALREADY_PAID",
  "errorMessage": "Payment already completed"
}
```

### SERVICE\_UNAVAILABLE (503)

Return this error when your service is temporarily unable to respond, for example during maintenance or an outage.

| Property    | Value                |
| ----------- | -------------------- |
| HTTP Status | 503                  |
| Error Code  | SERVICE\_UNAVAILABLE |

```json theme={null}
{
  "error": "SERVICE_UNAVAILABLE",
  "errorMessage": "Service temporarily unavailable"
}
```

<Note>
  VTPE uses the `errorMessage` value to inform the customer. Use clear, concise messages so the customer understands what went wrong.
</Note>