DataSag guides · Updated 27 October 2026

Load analytics without blocking rendering on Astro

Use the platform's non-blocking external script mechanism and install the tracker once. Measure the published page before and after the change; script size alone cannot predict the effect on your website. This guide applies to Astro.

Start with the Astro installation

Paste the external script into the head of the .astro layout used by your pages. Keep its src and data attribute on the actual script element. Use is:inline to make the intent explicit and leave the external tracker outside Astro's script bundling.

A layout only covers pages that use it. Check content collection pages and standalone landing pages too. If using client-side transitions, test a full route sequence rather than assuming a fresh document load every time.

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.

Load analytics without blocking rendering in Astro

  1. Keep the external tracker in the shared .astro head with defer and the required data attribute. Preserve its unprocessed external-script behavior instead of importing the tracker as an application module.
  2. Measure the built, published page with the same device and network settings before and after the change. Check a content page that uses the layout rather than relying only on a local Astro preview.
  3. For ClientRouter navigation, inspect repeated execution separately from initial download size. Avoid data-astro-rerun unless you have a specific lifecycle reason and have verified that the tracker will not register its global listeners again.

Initial loading is non-blocking and the tested Astro transition sequence adds no accidental tracker re-execution cost.

Complete the collection checks

  1. Record a baseline of the published page using the same browser, device emulation and network settings you will use for comparison. Include a representative content page, not only the homepage.
  2. Use defer for a normal external HTML script, or the framework-specific loading strategy shown in the installation example. Do not add a parser-blocking synchronous script as a shortcut.
  3. Keep one installation in the shared document or layout. Duplicate execution adds work even if the browser reuses the downloaded file.
  4. Inspect the Network waterfall for tracker.js and /api/track. Compare transfer size, timing and request count on a cold load and a cached load.
  5. Check that measurement still starts at the intended point. Loading only after idle or interaction can omit short visits and early clicks; performance and coverage must be evaluated together.
  6. Repeat the measurements and record variability. Report measured results for your page rather than claiming a universal speed improvement or zero performance cost.
// Browser Console, after loading the published page:
performance.getEntriesByType('resource')
  .filter(entry => entry.name.includes('/tracker.js'))
  .map(entry => ({ url: entry.name, durationMs: entry.duration }));
// Cross-origin transfer details may be unavailable.

What a successful check looks like

The script uses a non-blocking loading mechanism, appears once and records the intended visits. Any performance claim comes from repeatable measurements of the actual site.

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 faster lab result does not prove every visitor has a faster experience. Avoid mixing a warm-cache result with a cold-load baseline.

Installation snippet for Astro

The shared installation belongs in the head of your shared .astro layout. Use this as the installation reference while checking the procedure above.

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

Related Astro guides

Full Astro setup guide · Search and AI visibility

References

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