Free llms.txt Checker and Validator
Check an llms.txt file against the llmstxt.org format, v2 included. Enter a site or paste the file to see every error and warning by line, and test its links.
Loading tool…
How it works
Enter a site or paste
A domain fetches /llms.txt. A full URL checks a file at any path, such as /docs/llms.txt.
Check the format
One H1, a > summary, then H2 sections that list [name](url) links. Each finding shows its line.
Check the links
Optional: up to 20 links are requested to find dead ones and ones that serve HTML instead of Markdown.
What changed in llms.txt v2?
A file at a subpath, such as /docs/llms.txt, covers the pages under that path. Pages can point to their llms.txt with rel="describedby" and to a Markdown version with rel="alternate" type="text/markdown". The Optional section is still allowed but no longer has a special meaning.
Is my file sent anywhere?
Pasted text is checked in this tab and not sent anywhere. For a URL, our server fetches the file (up to 1 MiB), the llms-full.txt next to it, the page it covers and, if you ask, up to 20 links. Nothing is stored.
Agents read your site. Give yours a browser.
Browser Harness lets Claude Code, Codex or Cursor open pages in your Chrome, logged in as you.