# Callback

Cryptobank will send a request to the URL you specified when the status of the order you have created changes to successful or canceled.

Response sample

```json
{
    "currency":  "USDT-TRX",   
    "id":  "374",   
    "status":  "SUCCESS",
    "sum":  "185",   
    "sum_currency":  "186",   
    "verify_hash":  "SECRET_HASH"     
}
```

* id — order ID in the cryptobank you saved after your purchase request.
* verify\_hash — a message signature that allows you to verify that the request came from a cryptobank.

Please note that the USDR amount \<sum> and the currency amount \<sum\_currency> may differ from the values set when the transaction was created (for example, if the end user transferred an amount different from the set one).

Make sure your code handles the value of each return parameter correctly.

Possible values of the status field:

* SUCCESS — transaction paid
* CANCEL — transaction cancelled

Verify\_hash transaction (example on PHP):

```php
$data = $_POST;
unset($data['verify_hash']);
ksort($data);
$dataString = serialize($data);
$checkKey = hash_hmac('sha1', $dataString, CALLBACK_API_KEY);
    
if ($checkKey != $_POST[''verify_hash'']) {
  return false;
}
```

Expected response if the event was successfully processed:

```json
{
   "success":  true
}
```

In case of a different answer, the cryptobank will continue sending the request until a correct answer is received, or until the limit set in the API settings is reached.


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# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://wiki.relictum.pro/developing/relictum-finance/callback.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.