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Directly import `waitUntil` in Workers for easily spawning background tasks

Aug 08, 2025

Workers

You can now import waitUntil from cloudflare:workers to extend your Worker's execution beyond the request lifecycle from anywhere in your code.

Previously, waitUntil could only be accessed through the execution context (ctx) parameter passed to your Worker's handler functions. This meant that if you needed to schedule background tasks from deeply nested functions or utility modules, you had to pass the ctx object through multiple function calls to access waitUntil.

Now, you can import waitUntil directly and use it anywhere in your Worker without needing to pass ctx as a parameter:

import { waitUntil } from "cloudflare:workers";

export function trackAnalytics(eventData) {
  const analyticsPromise = fetch("https://analytics.example.com/track", {
    method: "POST",
    body: JSON.stringify(eventData),
  });

  // Extend execution to ensure analytics tracking completes
  waitUntil(analyticsPromise);
}

This is particularly useful when you want to:

• Schedule background tasks from utility functions or modules
• Extend execution for analytics, logging, or cleanup operations
• Avoid passing the execution context through multiple layers of function calls

import { waitUntil } from "cloudflare:workers";

export default {
  async fetch(request, env, ctx) {
    // Background task that should complete even after response is sent
    cleanupTempData(env.KV_NAMESPACE);
    return new Response("Hello, World!");
  }
};

function cleanupTempData(kvNamespace) {
  // This function can now use waitUntil without needing ctx
  const deletePromise = kvNamespace.delete("temp-key");
  waitUntil(deletePromise);
}

Note

The imported waitUntil function works the same way as ctx.waitUntil(). It extends your Worker's execution to wait for the provided promise to settle, but does not block the response from being sent to the client.

For more information, see the waitUntil documentation.