Question 1

Does this crawl my whole site?

Accepted Answer

No — this audits a single URL you provide. It fetches the live page server-side and scores it; nothing is stored beyond the request.

Question 2

Why didn't it detect content rendered by JavaScript?

Accepted Answer

This tool reads the raw HTML response, so content injected client-side by JavaScript frameworks after load may not appear in the audit. That's also what search engines index first — if the audit sees an empty page, so do they until the render queue catches up.

Question 3

What does it check?

Accepted Answer

Title and description length, H1 count and heading outline, canonical, indexability, language, structured-data validity and types, Open Graph and Twitter cards, favicon, word count, alt-text coverage, internal links, lazy loading, HTTPS, mobile viewport, server response time, HTML weight, compression, external scripts and third parties, security headers, and Cache-Control.