Why does Site Audit need JavaScript rendering after I install the snippet?
The Site Audit snippet is a script. When someone visits a page, it loads in their browser and applies the fixes you’ve published, such as new titles and meta descriptions.
For the audit to see those fixes, SpyFu’s crawler has to load your pages the way a browser does. That’s what JavaScript rendering does.
With rendering off, the crawler reads only your page’s raw code. It never runs the snippet, so it can’t see your fixes, and it keeps reporting fixed pages as still needing work. This is true however you installed the snippet, whether through Google Tag Manager or in your site’s header.
To turn it on, go to your project’s crawl settings, find Rendering, and turn on JavaScript. That also turns on Load resources and XHR requests. Leave all three on: the crawler needs one to run the snippet, one to load it from SpyFu’s servers, and one to fetch your published fixes.
What you gain
Your audit confirms your fixes. Published fixes show up in your results, and your health score reflects the work you’ve done.
A fuller view of your site. The crawler sees content and links that load with JavaScript, so it can find pages and issues a raw-code crawl misses.
Results that match what visitors see. Your audit reflects the rendered page, not just the code underneath it.
What to plan for
Slower crawls. Each page loads completely, with its scripts, CSS and images, before the crawler moves on. That takes longer than reading raw code, so expect crawls to run longer than before.
More load on your server. Each page also loads its supporting files. The Crawl delay setting (2,000 milliseconds by default) controls how long the crawler waits between pages. If you’re on limited hosting, keep the delay where it is or raise it. If your site handles traffic well, you can lower it to speed crawls up.
The crawler may show up in your analytics. Your tracking tags run during the crawl, so they may count it as a visit. You can filter out the RSiteAuditor user agent.
Bot protection may block it. Cloudflare and similar tools can be stricter with crawlers that load pages like a browser. If pages come back blocked or empty, allow the RSiteAuditor user agent.
Your issue counts may change after the first rendered crawl. That’s the crawler seeing more of your site, not necessarily a change to the site itself.
What if I leave it off? Your published fixes still go live for visitors, because the snippet doesn’t depend on this setting. Your audit just can’t confirm them, so those pages keep showing as unfixed.