# Notifications

Notifications (a.k.a "Callbacks", "IPN") are used in 0xpay to alert users about events happenning to their merchants. Whenever something happens to your merchant, 0xpay will try to send a webhook to the **Notifications URL** that you've previously specified in [merchant settings](/integration-cookbook/getting-started/merchant-setup.md#notifications). 

{% hint style="warning" %}
Webhooks require [authorization](broken://pages/dtfqhMod9SYIPU0fzM4x) on your side, in order to verify the validity of message received.
{% endhint %}

{% hint style="success" %}
We guarantee that webhooks will come in described order, according to their tx status change.

*For example:* we won't send you a "Done" status webhook until you respond with success HTTP status to a "Pending" webhook that was sent earlier.
{% endhint %}

### **Notifications retry timeline:**

{% hint style="info" %}
In case your URL responds with a *non-success HTTP status* – the notification will be retried **10 times,** with initial delay of **10 minutes,** each new retry triggered **15 minutes** later, up to a maximum of **60 minutes.** In total, we are going to try and notify you for **8 hours.**
{% endhint %}

| Number of Retries | Timeout |
| ----------------- | ------- |
| Retry #1          | 10 min  |
| Retry #2          | 25 min  |
| Retry #3          | 40 min  |
| Retry #4          | 55 min  |
| Retry #5-10       | 60 min  |

Check out notification examples on the next page.


---

# 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://docs.0xpay.app/public-api/notifications.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.