DataSag guides · Updated 27 October 2026

Track custom events on Next.js Pages Router

Use data-datasag-goal for a click goal, or call window.datasag.track after a completed action. Choose a stable event name and distinguish a click from a successful conversion. This guide applies to Next.js Pages Router.

Start with the Next.js Pages Router installation

Import Script from next/script in pages/_app.tsx. Keep Component and pageProps, and add the tracker once alongside the page component. The shared app stays mounted as users navigate between pages.

Do not install the same tracker in both _app and _document. Do not attach another pageview sender to router.events before testing the tracker's built-in History API handling.

Use the public project key from the DataSag project you are inspecting. A test on a preview domain does not confirm that the production domain has the same code or settings.

Track custom events in Next.js Pages Router

  1. Put the browser call in the component that receives confirmation of the action. Keep API routes, getStaticProps, and getServerSideProps responsible for server work; they cannot invoke the visitor window API.
  2. Leave the tracker in _app and use a typed optional browser helper from the action component. Do not reinstall the Script in each page just to make an event handler find it.
  3. Test the event after direct entry and after a Next.js Link transition. Submit a failing attempt too. Inspect the agreed eventName and ensure a route-change listener has not also attached the same action callback.

A successful browser action emits the named event in either entry mode without depending on a duplicate page script.

Complete the collection checks

  1. Write the event definition first. For example, signup_click means a visitor pressed a signup link, while signup_completed means your application confirmed account creation.
  2. For click intent, add data-datasag-goal to the element. The tracker delegates clicks, so you do not also need a JavaScript handler for the same goal.
  3. For a completed action, call the JavaScript API in the success handler. Wait for the tracker to be available. An optional guard avoids a crash but intentionally drops the event if the tracker has not loaded.
  4. Send only the context needed for the report, such as a form or plan name. Do not include email addresses, passwords, payment details or freeform form contents.
  5. Complete one successful and one failed attempt. Inspect /api/track for the exact eventName and properties. Only the successful attempt should emit a completed-action event.
  6. Check the event report available to your plan. Collection and access to reports are separate; review current plan details before depending on a particular report.
<!-- Click intent: use this OR your own click handler -->
<a href="/signup" data-datasag-goal="signup_click">Create account</a>

// JavaScript: inside the confirmed-success handler
window.datasag?.track('signup_completed', { form: 'main_signup' });

Use a browser event handler in your React component. Wait for the action to succeed before calling the global API; a button click alone does not prove a signup completed.

What a successful check looks like

A controlled successful action produces one event with the agreed name. A validation failure does not emit a success event. Network evidence matches the report definition.

Record the public path you tested, the browser state, the approximate time and the observed request. Check one direct page load and one later navigation so the result covers more than the homepage.

Common mistake

A goal attribute on a submit button measures clicks, including attempts that fail. Do not report those clicks as completed signups or purchases.

Installation snippet for Next.js Pages Router

The shared installation belongs in pages/_app.tsx, alongside the page component. Use this as the installation reference while checking the procedure above.

import Script from "next/script";

// Alongside <Component {...pageProps} /> in pages/_app.tsx:
<Script
  id="datasag"
  src="https://www.datasag.com/tracker.js"
  data-datasag-key="YOUR_PUBLIC_KEY"
  strategy="afterInteractive"
/>

Related Next.js Pages Router guides

Full Next.js Pages Router setup guide · Search and AI visibility

References

Official Next.js Pages Router documentation covers the integration point. For DataSag data handling, read the privacy policy. Use support if a request fails after these checks.