> For the complete documentation index, see [llms.txt](https://docs.0xprocessing.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.0xprocessing.com/0xprocessing-api-v1/webhooks/webhooks-for-payment-without-fixed-amount.md).

# Webhooks for Payment without fixed amount

Enable webhook notifications for flexible payment forms, ensuring real-time updates for transactions without fixed amounts in your crypto payments.

## Webhook response

The deposit report is implemented by means of webhooks.

For more information on setting up Webhooks, see the **Setting up Webhooks.**

Set the Webhook URL in the menu **Settings → API → Webhook URL**. **HTTPS (TLS/SSL) is required.**

**Webhook password** - password required to verify the payment signature

**Webhook URL** - the endpoint where 0xProcessing sends payment status notifications.

**Request method:** POST

**Response Type:** JSON

**Parameters:**

<table><thead><tr><th width="185">Name</th><th width="461">Description</th><th>Type</th></tr></thead><tbody><tr><td>PaymentId</td><td>Transaction ID in the 0xProcessing system</td><td>Integer</td></tr><tr><td>MerchantId</td><td>Merchant ID in 0xProcessing system</td><td>String</td></tr><tr><td>ShopId</td><td>Merchant ID in 0xProcessing system</td><td>String</td></tr><tr><td>Amount</td><td>Payment amount in cryptocurrency</td><td>Double</td></tr><tr><td>AmountUSD</td><td>Payment amount in USD equivalent</td><td>Double</td></tr><tr><td>TotalAmount</td><td>Full amount received in the cryptocurrency without fee</td><td>Double</td></tr><tr><td>TotalAmountUSD</td><td>Full amount received in USD equivalent without fee</td><td>Double</td></tr><tr><td>Currency</td><td>Payment currency</td><td>String</td></tr><tr><td>Email</td><td>Payer's e-mail</td><td>String</td></tr><tr><td>Status</td><td><p>Payment status</p><p>Possible values are:</p><p><strong>Success</strong> - payment has been executed successfully</p><p><strong>Canceled</strong> - the payment has been cancelled. The amount has been credited to the wallet indicated on the payment form after the payment window is closed (payment window 30-50 min). The amount has not been transferred to the wallet specified in the payment form.</p><p><strong>Insufficient</strong> - the deposit amount is less than the minimum amount, and the payment is assigned the status <strong>"Insufficient"</strong>. You will not be able to confirm the payment data without an additional payment</p></td><td>String</td></tr><tr><td>BillingID</td><td>Unique payment identifier in the system from which the payment is made</td><td>String</td></tr><tr><td>Signature</td><td>Checksum to verify the authenticity of the request (to ensure that the request came from 0xProcessing)</td><td>String</td></tr><tr><td>Insufficient</td><td><p>If the insufficient payments will be manually confirmed by support as successfully made.</p><p>You will receive a second callback with <strong>Success</strong> status and <strong>insufficient=true</strong> flag, which will transfer information about the (underpaid) amount actually received. You need to process this callback on the payment generation side and change the originally generated payment in accordance with the actual funds received</p></td><td>Boolean</td></tr><tr><td>ClientId</td><td>Unique client ID in your system</td><td>String</td></tr><tr><td>TxHashes</td><td>Successful transaction hash(es)</td><td>String []</td></tr><tr><td>Senders</td><td>Sender wallet address(es). Note: Currently works for Tron, BNB, Ethereum, Arbitrum, Avalanche, Polygon, Base, OpBNB, Optimism, HypeEVM, Robinhood chains.</td><td>String []</td></tr></tbody></table>

#### **If you want to know how to test callbacks? please follow** **the link**

**Signature check:**

1\. A string of the following form must be generated: **"PaymentId":"MerchantID":"Email":"Currency":"Password"** (WebhookURL link password)

Without quotation marks through a colon. **Example:** 12345:Qtfxhgy43:<test@test.com>:USDT (ERC20):qwerty

2\. Encrypt the resulting string using the MD5 algorithm

<https://emn178.github.io/online-tools/md5.html>

3\. Compare the resulting string with the one received in the webhook

```javascript
"Signature":"a5510c8c3e657ffd8229813749cd20ec"
```

4\. If the strings are the same, **return HTTP Status 200** (Required). Our server expects a response to the webhook within a 3-second timeout period. If the response is not received within these 3 seconds, the system considers the delivery failed.

If the callback is not delivered successfully, the system retries delivery up to 31 times with an interval of 15 seconds. If the webhook still fails to be delivered, the system sends a notification to the merchant's account email indicating a problem with the WebhookURL.

**Example Webhook JSON:**

{% code lineNumbers="true" %}

```json
                        {
                        "PaymentId":10453,
                        "MerchantId":"Asv0232SSd",
                        "Amount":0.00264765,
                        "TotalAmount":0.00264765,
                        "Currency":"BTC",
                        "Email":"test@test.com",
                        "Status":"Success",
                        "Signature":"a5510c8c3e657ffd8229813749cd20ec",
                        "BillingID":"13304",
                        "AmountUSD":115.0,
                        "TotalAmountUSD":115.0,
                        "Insufficient":false,
                        "Test":false,
                        "ClientId":"1000",
                        "TxHashes":["0e61e33a0c02204c41ac210c2fcffda4bea4399792acc49479aa8374465ef63a"],
                        "Senders":["bc1a5510c8c3e657ffd8229813749cd20ec"]
                        }
```

{% endcode %}

{% hint style="warning" %}
When processing callbacks, you MUST use the **PaymentId** parameter **from the callback 0xProcessing** as an additional validation factor.
{% endhint %}