Next.js (Pages Router) Step 1: Add CDN to pages/_document.tsx import { Html, Head, Main, NextScript } from 'next/document'; export default function Document() { return ( <Html> <Head> <link rel="stylesheet" href="https://cdn.jsdelivr.net/gh/AOSSIE-Org/SocialShareButton@v1.0.3/src/social-share-button.css" /> </Head> <body> <Main /> <NextScript /> <script src="https://cdn.jsdelivr.net/gh/AOSSIE-Org/SocialShareButton@v1.0.3/src/social-share-button.js"></script> </body> </Html> ); } Step 2: In your component: import { useEffect } from 'react'; export default function Header() { useEffect(() => { new window.SocialShareButton({ container: '#share-button' }); }, []); return ( <header> <div id="share-button"></div> </header> ); }