Free Chrome extension

How does your page look to search engines and AI?

Audit the open tab in one click. Eleven analysis panes, Core Web Vitals read from the browser’s own performance timeline, and a robots.txt access matrix for 16 AI crawlers.

  • No account
  • No data collected
  • No server
  • Free forever
Notify me at launchWhat it does

🧩 Coming soon to the Chrome Web Store · Chrome 116+ · works in Edge, Brave, Opera and Vivaldi

Built by Kerem Gezergün

The Crawlseer Overview pane: an SEO score out of 100 with the breakdown across five categories
Why Crawlseer

Measurement, not guesswork

Every finding comes either from the browser’s own measurement or from a published specification — and the interface tells you which.

  • Real Core Web Vitals

    LCP, CLS and TTFB are read from the browser’s performance timeline rather than estimated. LCP is broken into its four sub-parts and CLS uses the session-window rule.

  • 16 AI crawlers

    robots.txt rules for GPTBot, ClaudeBot, PerplexityBot, Google-Extended and the rest are resolved per RFC 9309. User-triggered fetchers are listed separately.

  • Raw HTML vs rendered DOM

    The HTML the server sent is compared with the page the browser built, showing exactly what a bot that does not run JavaScript would miss.

Eleven analysis panes

One page’s technical SEO, end to end

Overview · Headings · Hreflang · Links · Images · Schema · Social · Performance · Keywords · Crawlability · AI Visibility

Which bots can actually get in?

robots.txt is resolved, not just read. When a crawler has its own named group the wildcard group stops applying entirely — a distinction most tools miss, and one that produces false "allowed" verdicts.

  • A matrix split into training, citation and search groups
  • X-Robots-Tag and Cloudflare Content-Signal parsing
  • The sitemap index tree — is your page in it or not
  • Sitemap URLs declared in robots.txt but unreachable
The Crawlability pane: a matrix showing allowed and blocked status for each AI crawler

Can AI see you?

The AI Visibility pane examines whether your content is fit to be cited by generative search engines across seven blocks, and states the evidence level behind each finding: documented, or measured.

  • AI Overviews eligibility — nosnippet and max-snippet checks
  • Raw-vs-rendered delta and JavaScript dependency ratio
  • Schema against visible text
  • Citability, date consistency and agent readiness
The AI Visibility pane: AI Overviews eligibility, raw-vs-rendered delta and schema matching

Schema fields, against 2026 rules

JSON-LD, Microdata and RDFa, with @graph flattening and array @type support. Where several nodes share a type each is validated separately, and the report states in how many the field is present.

  • Required and recommended field checks for 21 types
  • Types that no longer produce rich results (FAQPage, HowTo) flagged
  • Invalid JSON-LD and dangling @id references
  • Structured data compared with the text on the page
The Schema pane: field validation badges for an Organization type and the JSON-LD dump

Is the hreflang actually valid?

Language codes are validated with the browser’s own BCP 47 resolver. Case differences are tolerated, while classic mistakes like en-UK are caught and the correct form (en-GB) is shown.

  • x-default and self-reference checks
  • Relative URLs and duplicate language codes
The Hreflang pane: the language tag table with invalid region code and relative URL warnings
Privacy

Your data never leaves your device

That is the architecture, not a slogan: there is no backend, so there is nowhere for data to be sent.

  • No server

    The extension has no backend. Every analysis runs in your browser.

  • No URLs stored

    Score history keeps an irreversible SHA-256 digest of the page address, not the address itself.

  • No third-party code

    The package contains no external libraries and loads no remote code.

  • Clear it in one click

    The "Clear history" button removes everything stored — you do not have to uninstall.

Read the full privacy policy →

FAQ

Common questions

Is it really free, or will it start charging?

Everything offered today is permanently free, and that is written into the privacy policy as a binding commitment. No existing feature will move behind a paywall.

Why does it ask for extra permission for some features?

Only two features do: broken-link checking and redirect detection. Both need to send requests to the targets of links on the page, and no request is made before you grant permission.

Do the Core Web Vitals match Search Console?

No, and that is deliberate. Crawlseer measures lab data: what happened on your device, on your connection, in that particular load. Search Console reports field data from real users.

Is the measurement valid if the page loaded in a background tab?

It is not, and the extension tells you so. A background tab does not paint until you look at it, so LCP would measure how long the tab waited rather than how fast the page is.

How do I delete my data?

In the Overview pane, the "Clear history" link under the trend chart removes all stored score history. Uninstalling the extension removes everything, including the theme preference.

Which browsers does it work in?

Chrome 116 and later. It is built on Manifest V3, so it also runs in Chromium-based browsers such as Edge, Brave, Opera and Vivaldi.

Make your next audit take three seconds

One email is all it takes to hear about Crawlseer when it reaches the Chrome Web Store.

Notify me at launch