> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ultravox.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Error Handling & Retries

> Understand how Ultravox automatically retries failed webhook deliveries with exponential backoff to ensure reliable event notifications.

## Retrying Failed Webhook Event Deliveries

If your webhook endpoint is temporarily unavailable or returns an error status code (e.g. 4xx or 5xx), Ultravox will automatically retry delivery using an exponential backoff strategy.

We'll make up to 10 retry attempts over several hours as follows:

* First retry will occur approximately 30 seconds later.
* Subsequent retries will double the retry interval. (e.g. second retry again after 1m, third retry after 2m, etc.)
* Total of 10 retries.

For permanent failures or extended downtime, you can always use our REST API to retrieve information about any calls/events you may have missed.

## Keep Building

* Learn about all [Available Webhooks](./available-webhooks) you can subscribe to
* Implement [Webhook Security](./securing-webhooks) to protect your endpoints
* Check out our [API reference](/api-reference/webhooks/webhooks-list) for webhook management endpoints