What Our Scanner Actually Checks and Why It Matters

When people see a score from our scanner, the first thing they ask is what it's actually measuring. It runs dozens of different checks, not a handful, and not just PageSpeed. The checks span several categories — some that matter directly to Google Search, some that measure page experience, and some that simply reflect good technical implementation. So when I say PageSpeed alone doesn't tell you much, this is why.

On the performance side, we're measuring Time to Interactive, First Contentful Paint, Speed Index, PageSpeed on both mobile and desktop, Largest Contentful Paint, Interaction to Next Paint, Cumulative Layout Shift, Time to First Byte, and server response time. Core Web Vitals are used by Google's ranking systems. The scanner also measures surrounding performance metrics such as FCP, TTFB, and Speed Index because they help diagnose why a page feels slow. Those diagnostic metrics are not all separate direct Google ranking factors.

Images get a full category. We check whether the site is using modern formats like WebP or SVG, how well images are compressed, whether responsive image attributes are configured correctly, whether lazy loading is enabled, and whether alt text is actually present. Unoptimized images are one of the most common reasons a site underperforms, and it's almost always fixable.

Accessibility is in there because it matters for usability and implementation quality. We check for alt text on images, proper labels on form inputs, accessible button text, critical blockers, and whether a language is declared on the HTML element. These are not all direct Google ranking signals, but they reflect how carefully a site was built and whether real people can use it.

Security is a full sweep covering HTTPS, redirect behavior, mixed content, Content Security Policy, HSTS, X-Content-Type-Options, X-Frame-Options, Referrer-Policy, and Permissions-Policy. HTTPS has search relevance, and the remaining headers are security and implementation best practices rather than direct Google ranking factors. They still matter for protecting the site and its visitors.

SEO basics that still get missed constantly. Title tag, title length, meta description, canonical tag, Open Graph data, Twitter card metadata, structured data presence, and JSON-LD validity. The title and canonical carry real weight, but not every one of these is a mandatory ranking signal. Meta descriptions influence clicks rather than rankings directly, and social metadata shapes how a page looks when shared. They all deserve attention, just not all for the same reason.

Document structure checks whether the page is built correctly at the HTML level, including DOCTYPE, valid structure, charset declaration, viewport meta, and the presence of the core HTML elements. Past that, heading structure gets its own pass. Whether an H1 is present and whether the heading hierarchy is logical and clearly communicates the primary topic. More than one H1 is not automatically a failure, but the page should have a clear primary topic and a meaningful heading structure.

Crawlability covers robots.txt, sitemap.xml, and whether those files are actually accessible and configured correctly. A sitemap that exists but returns errors makes URL discovery and crawl efficiency less reliable, and it signals a configuration problem worth fixing. URL integrity checks internal links, broken links, redirect loops, redirect chains, and orphan pages. A clean internal link structure helps Google understand site architecture, and redirect chains slow everything down across the board.

Indexing checks catch pages that are accidentally blocking themselves. Noindex tags, canonical signals, whether the canonical URL is itself indexable. This one surfaces more problems than most people expect. On the optimization side, we're looking at render-blocking resources, HTML minification, compression via GZIP or Brotli, browser caching, and cache header configuration. These details compound. A site that doesn't cache properly is slower on every single visit.

Mobile gets checked for responsive layout, viewport configuration, horizontal overflow, and whether navigation actually works on a phone. At this point Google indexes mobile first, so if your site doesn't work on a phone, the desktop version matters less than you think. Infrastructure checks cover HTTP/2 or HTTP/3 support and keep-alive, both of which affect speed at the server level. Then social metadata, favicon presence, console errors, and broken scripts round out the rest.

A strong PageSpeed score tells you one part of the story. A high score on our scanner tells you more. It means the site has a strong technical implementation across the categories the scanner evaluates — performance, security, SEO, accessibility, crawlability, and structure. It is not proof that Google will rank the site, but it means the technical foundation is in place. Most sites, including ones that look polished and professional, come in well below that. Not because the design is bad. Because entire categories of signals were never addressed. The clients didn't know to ask, and the people who built the sites didn't know to check. Or they did know and just didn't do the work.

The full checklist is below. Go through it. See where your site stands. If you want the actual data instead of guessing, run it through the scanner.