Custom limits
Last updated Apr 21, 2026 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:
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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description: Create a dynamic dispatch Worker to route incoming requests to user Workers in your dispatch namespace. title: Dynamic dispatch Worker image: https://developers.cloudflare.com/cloudflare-for-platforms/workers-for-platforms/configuration/dynamic-dispatch/og.png?v=d1d1e631671f98a1
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