---
description: Set per-customer CPU time and subrequest limits on user Workers in Workers for Platforms.
title: Custom limits
image: https://developers.cloudflare.com/og-docs.png
---

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# Custom limits

Last updated Aug 24, 2026|Copy as Markdown|[View as Markdown](https://docs-durable-objects-instance-replaced-errors.previews.developers.cloudflare.com/cloudflare-for-platforms/workers-for-platforms/configuration/custom-limits/index.md)|[Agent setup](https://docs-durable-objects-instance-replaced-errors.previews.developers.cloudflare.com/agent-setup/)

Custom limits allow you to programmatically enforce limits on your customers' Workers' resource usage. You can set limits for the maximum CPU time and number of subrequests per invocation. If a user Worker hits either of these limits, the user Worker will immediately throw an exception.

## Set Custom limits

Custom limits can be set in the dynamic dispatch Worker:

```js
export default {
	async fetch(request, env) {
		try {
			// parse the URL, read the subdomain
			let workerName = new URL(request.url).host.split(".")[0];
			let userWorker = env.dispatcher.get(
				workerName,
				{},
				{
					// set limits
					limits: { cpuMs: 10, subRequests: 5 },
				},
			);
			return await userWorker.fetch(request);
		} catch (e) {
			if (e.message.startsWith("Worker not found")) {
				// we tried to get a worker that doesn't exist in our dispatch namespace
				return new Response("", { status: 404 });
			}
			return new Response(e.message, { status: 500 });
		}
	},
};
```

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