---
title: Workers Fetch API can override Cache Rules
description: Customers who use Workers can now programmatically override Cache Rules for their individual requests.
image: https://developers.cloudflare.com/changelog-preview.png
---

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## Workers Fetch API can override Cache Rules

Apr 04, 2025 

[ Cache / CDN ](https://developers.cloudflare.com/cache/) 

You can now programmatically override Cache Rules using the `cf` object in the `fetch()` command. This feature gives you fine-grained control over caching behavior on a per-request basis, allowing Workers to customize cache settings dynamically based on request properties, user context, or business logic.

#### How it works

Using the `cf` object in `fetch()`, you can override specific Cache Rules settings by:

1. **Setting custom cache options**: Pass cache properties in the `cf` object as the second argument to `fetch()` to override default Cache Rules.
2. **Dynamic cache control**: Apply different caching strategies based on request headers, cookies, or other runtime conditions.
3. **Per-request customization**: Bypass or modify Cache Rules for individual requests while maintaining default behavior for others.
4. **Programmatic cache management**: Implement complex caching logic that adapts to your application's needs.

#### What can be configured

Workers can override the following Cache Rules settings through the `cf` object:

* **`cacheEverything`**: Treat all content as static and cache all file types beyond the default cached content.
* **`cacheTtl`**: Set custom time-to-live values in seconds for cached content at the edge, regardless of origin headers.
* **`cacheTtlByStatus`**: Set different TTLs based on the response status code (for example, `{ "200-299": 86400, 404: 1, "500-599": 0 }`).
* **`cacheKey`**: Customize cache keys to control which requests are treated as the same for caching purposes (Enterprise only).
* **`cacheTags`**: Append additional cache tags for targeted cache purging operations.

#### Benefits

* **Enhanced flexibility**: Customize cache behavior without modifying zone-level Cache Rules.
* **Dynamic optimization**: Adjust caching strategies in real-time based on request context.
* **Simplified configuration**: Reduce the number of Cache Rules needed by handling edge cases programmatically.
* **Improved performance**: Fine-tune cache behavior for specific use cases to maximize hit rates.

#### Get started

To get started, refer to the [Workers Fetch API documentation](https://developers.cloudflare.com/workers/runtime-apis/fetch/) and the [cf object properties documentation](https://developers.cloudflare.com/workers/runtime-apis/request/#the-cf-property-requestinitcfproperties).

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