---
description: AbortController, AbortSignal, and WritableStream no longer throw when constructed during module evaluation.
title: AbortController and AbortSignal can be created at global scope
image: https://developers.cloudflare.com/changelog/post/2026-08-19-abort-signal-global-scope/og.png?v=b99437fda9621c10
---

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August 19, 2026

## AbortController and AbortSignal can be created at global scope

[Workers](https://developers.cloudflare.com/workers/)

Copy as Markdown| [View as Markdown](https://developers.cloudflare.com/changelog/post/2026-08-19-abort-signal-global-scope/index.md)| [Agent setup](https://developers.cloudflare.com/agent-setup/)

`new AbortController()`, `AbortSignal.abort()`, `new WritableStream()`, and `request.signal` no longer throw when used during module evaluation (that is, at the top level of your Worker module, outside of a request handler). Previously, these APIs required an active request context and would throw if called at the top level.

```js
// This now works — no error during module startup
const controller = new AbortController();

export default {
	async fetch(request) {
		// The signal can be used across requests
		return new Response("OK", { signal: controller.signal });
	},
};
```

Signals can also be observed and aborted across different requests, making it easier to coordinate cancellation in long-lived Workers such as Durable Objects.

`AbortSignal.timeout()` still requires an active request context because it needs to schedule a timer.

For more details, refer to the [AbortController documentation](https://developers.cloudflare.com/workers/runtime-apis/web-standards/#abortcontroller-and-abortsignal).

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