Next.js

Use the Script component so the line loads on every route. Page changes inside the app are counted on their own.

App Router (app/layout.tsx)

import Script from 'next/script';

export default function RootLayout({ children }) {
  return (
    <html lang="en">
      <head>
        <Script defer data-site-id="YOUR-SITE-ID" src="https://spintaxifycms.com/js/analytics.js" strategy="afterInteractive" />
      </head>
      <body>{children}</body>
    </html>
  );
}

Pages Router (pages/_document.tsx)

Put the same Script line inside the Head of your custom document, or in pages/_app.tsx.

Deploy, then open the live site.

Check it works

Open your site in a normal browser window (not one where you are logged in as admin, if you excluded admin pages). Then open Analytics in Spintaxify. Within a few seconds Online now shows 1, and the setup card ticks Install the script.

Tip: your site ID is in Analytics → Settings → General. Copy the snippet from there and it is already filled in.