Free tool
llms.txt Validator
This free validator fetches llms.txt from any domain and checks its structure against the llmstxt.org convention: the H1 site name, summary blockquote, section headings, and link-list format. Support for llms.txt varies by system, and Google Search currently ignores it.
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.
Check the technical access surface.
These tools inspect individual inputs. Run the free technical access audit for a bounded crawler-controls and raw-HTML score plus prioritized observations. Neither result claims to measure indexing, rankings, or citations.
Run a free audit