Fix duplicate analytics pageviews on Flask with Jinja

Start with the Flask with Jinja installation

Put the deferred external script once in the shared Jinja base template under your application templates directory. Preserve existing blocks, imports and asset links. Confirm that render_template calls for your public routes select children of that base. The tracker remains an external browser script rather than Python application code.

Blueprint-specific template directories and independent render_template_string responses can bypass the base template. A child head block can replace inherited content unless it retains it. Inspect the generated response from the affected endpoint.

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.

Fix duplicate analytics pageviews in Flask with Jinja

1. Inspect the Jinja base, included head fragments and child overrides together. Calling super and copying the same script locally can render two installations through a single endpoint.
2. Check whether blueprint-specific pages load another analytics partial or frontend loader. Keep one intended owner in each final document rather than assuming every blueprint shares the application base.
3. Publish and test a normal endpoint and the affected blueprint route. Separate null-name pageviews from scroll and click events. Confirm the final HTML has one tracker after the complete Jinja inheritance chain is rendered.

The deployed Flask documents have a single installation after blueprint lookup and template inheritance.

Complete the collection checks

1. Open Network and filter /api/track. Reload once without clicking or scrolling. Inspect eventName in each payload: null identifies a pageview; scroll, click_heatmap and __datasag_engagement are other records.
2. Count rendered script elements with data-datasag-key. There should be one intended installation for this project. Search your code, site header settings, embeds and tag manager for additional copies.
3. Remove redundant script insertion mechanisms, keeping the site-wide installation. Two copies execute independently even when their browser download is cached.
4. Check for custom router listeners that manually send pageviews. The current tracker handles pushState, replaceState and popstate and ignores a repeated pathname. Do not add a second pageview implementation without a demonstrated gap.
5. Repeat a direct load, a second route and browser Back. Correlate pageview records with actual path changes. A query-only change on the same pathname is not a new pageview in the current tracker.

[...document.querySelectorAll('script[data-datasag-key]')]
  .map(script => ({
    src: script.src,
    key: script.getAttribute('data-datasag-key')
  }));

What a successful check looks like

A single installation and one pageview dispatch for each actual pathname change in the tested sequence. Additional engagement records remain available.

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

Comparing the total number of events with the number of pageviews produces a false duplicate diagnosis. Keep the event categories separate throughout the check.

Installation snippet for Flask with Jinja

The shared installation belongs in the head of the Jinja base template used by your routes. Use this as the installation reference while checking the procedure above.

<script defer src="https://www.datasag.com/tracker.js" data-datasag-key="YOUR_PUBLIC_KEY"></script>

Related Flask with Jinja guides

• Verify DataSag analytics
• Fix DataSag analytics not working
• Track custom events
• Track UTM campaigns
• Measure AI referral traffic
• Configure CSP for DataSag analytics
• Exclude your own analytics visits
• Load analytics without blocking rendering

Full Flask with Jinja setup guide · Search and AI visibility

References

Official Flask with Jinja documentation covers the integration point. For DataSag data handling, read the privacy policy. Use support if a request fails after these checks.