Free tool
llms.txt Validator
Publishing an llms.txt only helps if it actually parses. This free validator fetches the llms.txt from any domain and checks it against the llmstxt.org spec — the H1 site name, the summary blockquote, section headings, and the link-list format — and tells you exactly what to fix. If the file is missing, it points you to our generator to create one.
We fetch the site's /llms.txt directly and check it against the llmstxt.org spec.
How to use it
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1
Enter a domain. The validator fetches its /llms.txt directly.
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2
Review the pass/fail result for each spec rule.
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3
Fix the flagged lines and re-run — or generate a fresh file with the llms.txt Generator.
FAQ
What does a valid llms.txt look like?
A markdown file starting with a single H1 (your site name), an optional one-line summary as a blockquote, then H2 sections each containing a bullet list of "[Title](URL)" links to your key pages.
My llms.txt is a plain list of URLs — is that valid?
Not per the spec. Bare URLs still give AI systems something, but the llmstxt.org format expects markdown links with titles inside H2 sections, which is what this validator checks for.
The validator says my file is missing but I uploaded it — why?
The file must be served at the domain root as /llms.txt with an HTTP 200 status. Common misses are serving it from a subdirectory, a redirect to an HTML page, or a 404 behind a CDN rule.
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