Free validator · works before you publish
Check the signals your page sends before anyone else reads them
Search engines, social platforms and AI answer engines all read the same head of your page first: title, description, canonical, Open Graph, Twitter cards, JSON-LD. Paste your page's HTML below — published or not — and get a scored verdict on each signal with a fix list written from your actual markup.
Why these signals, specifically
The head of a page is its handshake with every machine that will ever present it. The title and description are what a search result is made of. The canonical tells crawlers which of several near-identical URLs is the real one. Open Graph and Twitter cards are, quite literally, what your link looks like when anyone shares it — no image means no picture, however good the page is. JSON-LD is the page stating in plain structured terms what it is, which is what rich results and AI answers quote. And one stray “noindex” in a robots tag quietly removes the page from search altogether — which is why this validator checks for it first-class and flags it as the emergency it usually is.
Everything runs in your browser. Your HTML is never uploaded — paste a staging page, a client's page, a competitor's page source; nobody sees it but you.
Questions
Why paste HTML instead of entering a URL?
Because the most valuable moment to check a page is before it is live. A URL checker can only audit what is already published; pasted source works on a page still in your editor, on staging, or behind a login — and it needs no server, no crawler permission and no waiting. To get a published page's source: open it, press Ctrl+U (View Source), copy everything, paste it here.
What exactly does the validator check?
Sixteen signals: the title tag and its length, the meta description and its length, the canonical URL, the robots directive (a noindex is flagged as the emergency it usually is), viewport and charset, the five core Open Graph tags plus whether the OG image and URL are usable, the Twitter card set with its Open Graph fallbacks, JSON-LD — parsed for real, so invalid JSON fails — and the page's language and H1 count. Each check explains what it found in your actual markup, not a generic tip.
How is the score calculated?
The score starts at 100. Each failing check deducts 15 and each “improve” check deducts 5, with the result floored at zero. The weights are deliberately uneven: a noindex or a missing share image costs real visibility, while a slightly long title mostly costs polish. The verdict bands are Strong (90+), Mostly there (70+), Gaps to fix (45+) and Critical gaps (below 45).
Can this validator check its own page?
Yes — there is a button that loads this page's own HTML into the box. It is the same test we run on ourselves in this site's automated audit, which requires every page here to carry a canonical URL, matching Open Graph tags and valid JSON-LD with a breadcrumb trail.