How ProofRank measures a website

What is measured

Each scan fetches the homepage and up to 24 linked pages, then runs checks in five categories: performance, SEO, accessibility, security and reliability. Performance uses real-user Core Web Vitals, or server response time and compression when none exist. SEO covers indexability, titles and descriptions (presence, uniqueness and length), headings, Open Graph tags, canonical links, structured data, redirect chains, internal links (nofollow, links to error pages, redirects or non-canonical addresses, pages nothing links to), near-duplicate pages without a canonical, canonical and hreflang targets, one title and description per page, thin pages, Open Graph and X cards, HTML size, structured data required properties, AI crawlers that robots.txt allows but the server refuses, main text that needs JavaScript, llms.txt, CSS and JavaScript open to Googlebot, broken links to other sites, the site's own images, scripts and stylesheets (caching, formats, dimensions, lazy loading), and the sitemap (reachable, its URLs answering, indexable, final and canonical, indexable pages listed, believable dates). Security adds email authentication (SPF, DMARC), CAA, DNSSEC, security.txt, known-vulnerable JavaScript libraries and integrity hashes; reliability adds domain and certificate expiry, IPv6 and nameservers. Up to 25 addresses linked from the sampled pages are fetched for their status. The overall score combines the categories that could be measured.

Missing is not zero

If a check cannot run, for example because a page needs JavaScript we did not execute, it is marked Not measured and left out of the score. A report is provisional until at least 90% of checks have run, and authoritative after that.

Critical failures

Some failures limit the overall score: at most 39 when the homepage answers with an error or our crawler receives a different homepage than a browser; at most 59 without HTTPS or when the homepage is blocked from search; at most 79 when under 80% of sampled pages answer, or a critical accessibility check fails on more than 20% of pages.

Ranking

A site ranks when its report is authoritative, every category has a score with at least half of its checks run, confidence is at least 50%, and the crawler and a browser received the same homepage.

Verification before penalty

Unusual results are checked again before they can lower a score. A single timeout does not decide your rank.

Fixes and regressions

Owners can mark an item fixed. It becomes Verified fixed only after a new scan confirms it. If the problem returns, the item reopens as Regressed.

AI crawler access

We report whether GPTBot, OAI-SearchBot, ChatGPT-User, ClaudeBot, Claude-SearchBot, PerplexityBot and Googlebot can read each page, with the robots rule, header or firewall response behind it. Blocking a crawler can be a deliberate choice, so this is reported and not scored.

Paid features

Plans unlock owner tools and capacity. They never change a score or organic rank. Paid placements are labelled "Sponsored" or "Featured placement" and appear outside ranked lists. Free submissions add the Featured on ProofRank badge to their site as a followed link. Pro, Spotlight and Priority Review skip it. Nothing else is required: no tag, embed or other site change.