Workers - Request.signal will be enabled by default in Workers on November 17

Starting November 17, 2026, Workers with a compatibility date of 2026-11-17 or later will receive client disconnection events through request.signal by default. Use these events to stop unnecessary work when a client leaves. You will no longer need the enable_request_signal compatibility flag for these dates.

We introduced this feature in May 2025. You can log cancellations, clean up resources, or cancel operations that accept an AbortSignal.

For example, this Worker logs a client disconnection and cancels an outgoing request:

src/index.jsjs

export default {
	async fetch(request) {
		request.signal.addEventListener(
			"abort",
			() => {
				console.log("Client disconnected");
			},
			{ once: true },
		);

		return fetch("https://example.com/slow-response", {
			signal: request.signal,
		});
	},
};

src/index.tsts

export default {
	async fetch(request): Promise<Response> {
		request.signal.addEventListener(
			"abort",
			() => {
				console.log("Client disconnected");
			},
			{ once: true },
		);

		return fetch("https://example.com/slow-response", {
			signal: request.signal,
		});
	},
} satisfies ExportedHandler;

Existing Workers keep their current behavior until you change their compatibility date or flags. To try this feature before November 17, keep your current date and add enable_request_signal to your compatibility flags.

With a compatibility date of 2026-11-17 or later, add disable_request_signal to opt out. This change does not enable request_signal_passthrough. Pass the signal explicitly, as the example does.

For more information, refer to the Request API and the Request.signal compatibility flag.