---
title: No Unwanted Polyfill.io
---

> Prevent duplicate polyfills from Polyfill.io.

## Why This Error Occurred

You are using polyfills from Polyfill.io and including polyfills already shipped with Next.js. This unnecessarily increases page weight which can affect loading performance.

## Possible Ways to Fix It

Remove all duplicate polyfills. If you need to add polyfills but are not sure if Next.js already includes it, take a look at the list of [supported browsers and features](/docs/architecture/supported-browsers).

## Useful Links

- [Supported Browsers and Features](/docs/architecture/supported-browsers)
