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WebsiteValidator

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Website Checker

Every module, one scan, one prioritised fix list

One scan, eleven modules, 986 rules. Every module scores out of 100 on its own and the overall score is their equal-weighted mean - so a site cannot hide a broken module behind a large one, and adding rules to a module does not change how much that module is worth.

Quick runs 93 high-signal checks in about 3 seconds, no browser. Full adds Core Web Vitals, the accessibility engines and a screenshot, and takes about a minute.

Try:
  • Free, no signupNo account, no card
  • No AI in the score986 deterministic rules
  • Nothing publishedYour scans stay yours
  • Answers in secondsQuick scan, no browser

What comes back is not a list of everything wrong. It is a ranked path: the fix that recovers the most points first, with the projected score after each one, so you can stop when the remaining work stops being worth it. Each finding carries the evidence that triggered it, a citable reference, and either a paste-ready fix or the steps to make one.

No language model decides any of it. Every status and every point traces to a deterministic rule with a declared confidence tier, which is why the same page scanned twice returns the same number - and why an AI system summarising your report is repeating a measurement rather than an opinion.

Why this matters

Nobody tells you what you are not looking at

A site can pass every SEO check and still be unusable with a keyboard, invisible to an AI assistant, or shut out of indexing by one line in a file you have never opened. Each tool reports on its own patch and says nothing about the rest. You find out from a customer, or you never find out at all.

What it costs you when this is wrong

  • One line in robots.txt takes the whole site

    A blanket Disallow, or a rule that shuts out GPTBot and ClaudeBot, lives in a file no page-level tool opens. Search engines and AI assistants stop fetching you, and the first symptom is traffic that quietly stops arriving.

  • The afternoon goes on the wrong fix

    Four tools give you four backlogs and no way to compare them. So the time goes on image alt text while the contact form still posts over plain HTTP and the browser warns every visitor who tries to use it.

  • The visitors who never tell you

    Someone navigating by keyboard meets a menu that only opens on hover, and an agent buying on a customer's behalf meets a button with no accessible name. Neither files a bug report - the order simply does not happen.

Why run it here

  • One problem is penalised once

    A rule marked as a rollup absorbs its children: they still run and still appear in the report as evidence, but only the parent costs points. A page with no FAQ content cannot be charged for it twice, once under SEO and again under answer-engine coverage.

  • A failed layer, not a failed scan

    Every layer of the scan is wrapped so that one timeout degrades that layer alone. The rest of the report still arrives, marked partial, with the layer that dropped out and the reason recorded - so you know exactly what the score does not include.

  • 511 of the 986 rules cannot cost points

    Detection is kept separate from scoring on purpose. A link that answered 403 is bot protection refusing our request rather than a dead link, so it is reported and never scored - and the same holds everywhere the right answer depends on your judgement rather than a specification.

This check runs on its own here, and as part of the full audit alongside the other 985 rules. Either way the findings carry their evidence and their citation, and the report is never published or kept.

How to improve your overall website score

A full audit returns findings across every module at once. Working in this order fixes the highest-impact problems first rather than the most numerous.

  1. Fix anything blocking indexing first — a stray noindex or a robots.txt disallow makes every other improvement irrelevant.

  2. Resolve critical accessibility failures next. They carry the highest weight, and several are also legal obligations.

  3. Add the security headers you are missing, which is usually the fastest large score movement available.

  4. Work through the SEO findings: unique titles and descriptions, one h1, a canonical on every page.

  5. Then the performance work, which is the most effort per point and best done once the rest is stable.

What happens when you run it

  1. Enter your address

    Just the domain is enough — example.com, with or without the https. No account, no card, no crawl of your whole site.

  2. We render it like a visitor

    Your page opens in a real browser and JavaScript runs to completion, so what gets audited is the page a person actually sees — not the raw HTML your server sent. A screenshot comes back with the report as evidence of exactly what we measured.

  3. You get findings you can act on

    Up to 986 checks run against that rendered page. Each finding names the rule, quotes the evidence found on your page, cites the public specification behind it, and says what to change. Nothing is a judgement call — run it twice on an unchanged page and the score is identical.

What runs this check

  • Real browser rendering
  • Core Web Vitals measurement
  • WCAG 2.2 rule engines
  • W3C conformance parsers
  • Live HTTP link resolution

Named because provenance is the product. Every finding in your report says which of these produced it, so you can check the reasoning rather than take a score on faith.

Questions

How long does a full scan take?
About a minute. It opens a real browser - once for rendering, once for Lighthouse, once for the WCAG engine, once for the screenshot. A Quick scan skips the browser entirely and answers in a few seconds using the high-signal rules.
Do I need an account?
No. Paste a URL and scan. Your history is scoped to your own browser and shown only to you.
Do you store my report?
The scan result is stored so you can return to the link. Every export - PDF, HTML, JSON, the AI fix plan - is generated on demand and never written anywhere.

Also checks

This page answers these searches too — they are the same job, so they share one page rather than being split across near-identical ones:

  • website validator
  • website audit tool
  • site checker
  • website analyzer

Other checkers

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No signup, no credit card. Quick answers in seconds; a full audit takes about a minute.

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