Upgrade the web. Automatically.

Just the polyfills you need for your site, tailored to each browser. Copy the code to unleash the magic:

<script src="https://cdn.polyfill.io/v2/polyfill.min.js"></script>

Polyfill.io reads the User-Agent header of each request and returns polyfills that are suitable for the requesting browser. Tailor the response based on the features you're using in your app, and see our live examples to get started quickly.

This site runs version 3.11.0 of the service. To get notified when we release new versions or push release candidates to our public QA environment, follow us on twitter at @polyfillio.

The polyfill service is developed and maintained by a community of contributors led by a team at the Financial Times. It evolved from a previous service developed by Jonathan Neal, and our cdn.polyfill.io domain routes traffic through Fastly, which makes it available with global high availability and superb performance no matter where your users are.

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