Learn · SEO Checks

SEO checks explained

Our engine runs >60 checks on every URL — on-page SEO, technical health, structured data, performance, links, and AI readiness. Each explainer below documents exactly what we test, the thresholds we use, and how to fix failures on WordPress, Shopify, Webflow, and other platforms.

Explainers

Check-by-check guides

Technical SEOCanonical tags explainedWhat canonical tags do, why they matter for SEO, and how our engine detects missing, duplicate, or misconfigured canonicals.7 min read On-Page SEOMeta descriptions explainedThe exact rules our checker applies to meta descriptions (missing, over 160 characters, duplicate) and a snippet that reproduces them.6 min read On-Page SEOTitle tags explainedThe exact title rules our checker applies (missing, under 30, over 60, duplicate) and where it can disagree with your browser.7 min read Structured DataStructured data (JSON-LD) explainedHow JSON-LD structured data helps search engines and AI systems understand your pages — and the four checks our engine runs.8 min read Technical SEOSecurity headers explainedWhat HSTS and X-Content-Type-Options headers do, why they matter for SEO trust signals, and how our engine checks them.6 min read On-Page SEOOpen Graph tags explainedWhat OG tags do for social sharing and AI visibility, and how our engine checks for missing og:title, og:description, and og:image.7 min read On-Page SEOHeading hierarchy: how our checker reads H1 to H6The three heading rules we apply (no H1, several H1s, skipped levels), what Google says about heading order, and where we disagree with your browser.7 min read On-Page SEOImage alt text: what our checker flags and whyThe one alt-text rule we apply, why it also flags alt="" on decorative images, what Google says, and a snippet to reproduce the result.7 min read Technical SEORobots.txt explainedWhat robots.txt does, how it controls search engine and AI crawler access, and how our engine checks for missing or overly restrictive files.7 min read PerformanceCore Web Vitals & performance explainedHow LCP, INP, CLS, and Lighthouse score affect SEO rankings — and how our engine checks real-user field data and lab metrics.9 min read Technical SEOInternal links & redirect chains explainedHow our engine counts redirect hops on every audit and finds broken internal links in a full crawl, with commands that reproduce both.6 min read On-Page SEOThin content explainedWhat thin content is, why it hurts rankings, and how our engine flags indexable pages with fewer than 300 words.6 min read AI ReadinessAI readiness checks explainedHow our engine scores your AI visibility — llms.txt, AI bot access, question headings, FAQ schema, and content chunkability.8 min read LinksLink health explainedOrphan pages, click depth, broken external links, excessive links, and generic anchor text — five checks for a healthy link profile.8 min read Technical SEOHTTPS & mixed content explainedHow HTTP-to-HTTPS redirects, mixed content, and www/non-www consistency affect SEO and how our engine checks them.7 min read

Questions

What people ask about our checks

How many SEO checks does the engine run?

Single-page mode runs 61 checks: technical health, on-page elements, structured data, links, AI readiness and CMS-specific probes. Every one of them has a documented threshold — the explainers here cover the highest-impact ones in detail, and the methodology page lists the scoring weights.

What is the difference between a warning and a critical issue?

Severity decides how much a failed check costs your score. Critical issues block indexing or break the page for crawlers (a missing title, a noindex you did not intend); warnings cost visibility without blocking it (a description over 160 characters, a missing canonical). Fixes in every report are ranked by that cost, not alphabetically.

Do these checks apply to every CMS?

The checks are platform-agnostic — they read the rendered HTML and the HTTP response. The fixes are not: each explainer links to platform-specific instructions for WordPress, Shopify and Webflow, because where you edit a canonical tag differs completely between them.

Where can I see these checks run on my own page?

Paste any URL into the checker. The report streams in check by check, shows which ones passed, and deep-links each failure to the explainer and the fix guide for your CMS. No signup and no email.

Run a full audit