HeadlarkFree SEO checker
Paste a URL to see what search engines and link previewers read from it today: title, meta description, Open Graph, X card, canonical, robots, headings, structured data and image alt text. You get a score, the problems in plain words, and previews of the Google result and the LinkedIn, Facebook, Slack and X cards.
Checks
Previews
Headlark writes these for you on every deploy: titles, descriptions, link previews, structured data and alt text, grounded in each page's content. Free for 25 pages.
Write these tags automatically: start freeWhat it checks
Only the HTML your server sends, the way Facebook, LinkedIn, Slack and X read it. Tags that JavaScript adds after the page loads don't count, because those previewers never run it. Nothing about you is stored: a shared result holds the URL, the checks and when they ran.
For a closer look at structured data, the structured data checker checks each JSON-LD block against the properties Google requires and recommends.
Fixing what it finds
The guides explain the usual causes: blank link previews, an og:image that doesn't show, missing meta descriptions and images without alt text.
Check a whole site
Some problems only show across many pages: two pages with the same title, descriptions copied from a template, link previews missing on every blog post. The site checker reads your sitemap, checks up to 50 pages and lists them with the affected URLs.