# Reconciling missing events

Shopify does not offer a strict guarantee on webhook delivery. In rare cases (and *usually* in high-volume situations), we've observed Shopify fail to send a webhook.

Quoting from [Shopify's recommendation](https://shopify.dev/apps/webhooks#implement-reconciliation-jobs) for this scenario:

> Your app shouldn't rely solely on receiving data from Shopify webhooks. Because webhook delivery isn't always guaranteed, you should implement reconciliation jobs to periodically fetch data from Shopify.

This applies to Mechanic tasks as well (which are, essentially, tiny apps).

For tasks that respond to events on Shopify resources, we recommend the following, using shopify/orders/create as an example:

1. Update the task code to mark orders as having been processed. This could take the form of an order tag (e.g. "processed-by-task-xyz"), or a metafield. Additionally, ensure that this code *skips* orders that are already marked as processed.
2. Add a [Mechanic scheduler subscription](/platform/events/topics.md#scheduler), like mechanic/scheduler/15min. Then, update the task code so that these scheduled runs are used to scan for and process new orders in the last 15 minutes that have not yet been processed. This is the reconciliation step, ensuring that all new orders are ultimately processed, one way or another.

## Example

{% embed url="<https://tasks.mechanic.dev/demonstration-auto-tag-new-orders-with-reconciliation>" %}


---

# 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://learn.mechanic.dev/core/shopify/events/reconciling-missing-events.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.