Website SEO Checker: How Ours Works and Why It's Free

Most website SEO checkers are lead-gen forms wearing a "free tool" costume. You submit a URL, get a score out of 100, and then hit a wall — the details require an email address, a signup, or a paid plan. This article explains how our checker works differently, what it actually checks, and how it decides on a score.

What does a website SEO checker actually need to check?

A score without transparency is a marketing number, not an audit. The checks that matter for most sites fall into six categories:

Technical SEO — can search engines access and index your pages correctly? This covers robots.txt, canonical URLs, redirect chains, crawl errors, and HTTPS. Technical issues are the highest-weighted category in our scorer because they block everything else.

On-page SEO — are your title tags, meta descriptions, H1/H2 structure, and keyword signals set up correctly? On-page signals are how you tell search engines what a page is about.

Performance (Core Web Vitals) — Google uses real Chrome user data (CrUX field data) to measure LCP, CLS, and INP on your pages. Lab scores from Lighthouse tell you potential; CrUX tells you what real visitors experience.

Structured data — JSON-LD schema markup (FAQPage, Product, Article, HowTo) gives search engines structured facts about your content. It's required for rich results and increasingly cited by AI systems.

Links — internal linking structure, broken link detection, and external link health. Internal links shape how PageRank flows through your site; broken links create dead ends for both crawlers and visitors.

AI visibility (GEO) — a newer category covering whether AI assistants like ChatGPT, Perplexity, and Claude can access, parse, and cite your content. Includes robots.txt AI-bot rules, llms.txt presence, FAQPage schema for answer extraction, and heading structure for content chunking.

How does our website SEO checker score results?

Every check returns a result with a severity: critical, warning, or info. The score uses these weights:

• Critical issues: 3× weight (they actively hurt indexing or ranking)
• Warning issues: 1× weight
• Info items: 0.25× weight (nice-to-haves, not critical)

Within each category, the score is max(0, 100 - weighted_penalty_points). Categories are then combined using weighted averages:

| Category | Weight | |---|---| | Technical | 25% | | On-page | 22% | | Performance | 18% | | Structured data | 15% | | Links | 15% | | AI visibility | 5% |

This weighting reflects what has the biggest impact on most sites. Technical issues are highest-weighted because a robots.txt block or misconfigured canonical can nullify everything else. AI visibility is currently 5% — a signal that it matters but shouldn't dominate the score for sites not targeting AI referral traffic.

Why does DeepSEOAnalysis show the full audit for free?

Three reasons:

1. The audit is the product. We want you to use the tool, get real value, and return when you need to monitor a site or run audits at scale. Locking the results behind a signup defeats that.

2. The score alone is useless. An "83/100" with no explanation is not an audit. It's a number. The value is in knowing which canonical tag is wrong, which H1 is missing, why your LCP score is slow, and what it would take to fix it. Withholding that information would make us indistinguishable from the checkers we're competing with.

3. It's how we built it for ourselves. DeepSEOAnalysis runs its own audit on deepseoanalysis.com. Our baseline score at launch was 92/100, and the detailed audit output told us exactly which issues to fix. We didn't need an email address to do that.

Paid plans add audit history, monitoring, scheduled re-audits, exports, and agency-scale multi-site workflows — capabilities that require infrastructure and ongoing compute. The audit itself stays free.

What does a website SEO checker miss?

Honest answer: a lot. Automated checkers are good at detecting structural issues — tags, schema, redirect chains, CrUX data, robots rules. They cannot:

• Read whether your content is accurate, authoritative, or genuinely useful
• Tell you if your keyword targeting matches actual search demand (that requires keyword research)
• Assess your backlink profile or domain authority (requires crawler access to external link graphs)
• Know whether your conversion rate on a page is low because of SEO or UX
• Predict algorithm changes

A website SEO checker is a starting point, not a strategy. Use it to find and fix the technical and structural issues that are actively holding rankings back — then layer in content quality, link building, and search demand research on top.

How does our checker handle JavaScript-rendered pages?

The engine crawls pages using standard HTTP (no headless browser). This mirrors how Googlebot handles most pages on its first crawl pass. If your site requires JavaScript to render critical content, title tags, or meta descriptions, the checker will see the same empty shell that Googlebot sees before it queues a JavaScript render.

For JavaScript-heavy sites, the main risk the checker flags is: structured data, meta tags, or canonical links injected only by JavaScript. If these are missing from the raw HTML response, the checker surfaces a warning.

How do I use a website SEO checker effectively?

1. Start with the critical issues. One critical issue (wrong canonical, blocked in robots.txt) matters more than ten info items.

2. Check multiple pages. Most website SEO problems are template-level — they repeat across every page generated by the same layout. Check a homepage, a product/service page, and a blog post to catch issues at each template level.

3. Re-run after fixes. The checker's value is in iteration. Fix critical issues, re-run, confirm they're resolved.

4. Don't chase 100/100. Some info items reflect best practices that don't apply to every site. A 94/100 with all critical and warning issues resolved is better than a 97/100 with hidden technical debt.

5. Check AI visibility if you care about ChatGPT/Perplexity referrals. The GEO score is separate from the main score and flags whether your site structure makes it easy for AI systems to cite you accurately.

Does the website SEO checker work on any URL?

Yes, with a few caveats. The checker fetches publicly accessible URLs. Pages behind a login wall, Cloudflare challenges, or rate limits that block our crawler will return incomplete data. If a page redirects more than five times or times out, the checker reports the redirect chain and stops.

It works on any domain — not just deepseoanalysis.com. You can run it on a competitor's URL to see where they have technical gaps, or on a client site before pitching a retainer.

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Ready to check your site? The full audit is at the top of this page — no signup, no email, no tricks.

For a step-by-step breakdown of what a technical audit covers, see: Technical SEO Audit: A 10-Step Checklist for 2026.