Search Overflow
ShippedRuns a real headless browser, not a guess

Rendering gate

Search engines render JavaScript. Most AI crawlers do not. A React site that looks perfect in your browser can be an empty shell to the thing deciding whether to cite you.

Two fetches, then a comparison

We take the server HTML exactly as a non-rendering crawler receives it, then render the same URL in a headless browser through Playwright. The gap between those two is what an AI crawler is missing.

It gates everything below it

If a page is client side only, telling you its product schema is incomplete would be noise. The schema is not incomplete, it is invisible. We report the cause and hold the symptoms until you fix it.

Schema hidden behind JavaScript is called out separately

Structured data injected by a tag manager or a client side script gets its own block level finding, because it is a common and expensive mistake. The schema validates perfectly in Google testing tools and is entirely absent to a crawler that does not execute scripts.

Questions

Does Google not render JavaScript?

Google does, on a delay. This check is not about Google. It is about the crawlers behind answer engines, most of which take the HTML they are given and move on.

More in Can AI engines read you?

Run it against your own site.

No signup, no card. It reports what it could not check as well as what it found.