Free tool
llms.txt validator
Check the llms.txt on any domain, or paste a draft, against the llmstxt.org format. Each issue comes with the line that caused it and how to fix it. No file yet? Generate one.
The rules it checks
- H1 with the site name
- The only required part of the format. It must be the first line, and there should be only one.
- Blockquote summary
- A line starting with > right after the H1 that says what the site is. Recommended, not required.
- H2 sections with file lists
- Key pages grouped under ## headings. A section named Optional marks links a model can skip when context is short.
- List items are links
- Each item reads "- [Name](url)", optionally followed by ": a short note".
- Absolute URLs
- Full https:// links, so a model reading the file on its own can follow them.
- Only H1 and H2 headings
- The format has no H3 or deeper. Free text between the summary and the first section is fine, as long as it has no headings.
FAQ
What does this validator check?
It reads your llms.txt and checks it against the structure described on llmstxt.org: one H1 first, an optional blockquote summary, then H2 sections whose list items are Markdown links. It also flags relative URLs and headings deeper than H2. When you enter a domain it first fetches https://yourdomain/llms.txt and tells you if the file is missing or served as an HTML page.
Is llms.txt an official standard?
No. It is a proposal from llmstxt.org. No major AI engine has said it relies on llms.txt to decide what to show or cite, and Google has said Search does not use it. Some AI coding tools and documentation sites do read it. A valid file is cheap to keep, but it is not a ranking lever.
My llms.txt shows my homepage instead. Why?
Many sites answer every unknown path with the homepage or a 404 page and still return HTTP 200. The validator reports that as not found, because a model would read HTML, not your file. Upload a plain text file named llms.txt to the site root.
Do the links have to be on my own domain?
No. The format allows any URL, for example docs hosted elsewhere or a GitHub repository. The validator only checks that each link is well formed and absolute; it does not open them.
Is my file stored?
No. The check runs on request and nothing is saved.
A clean llms.txt is a start. Are you in the answer?
AnswerTrack asks ChatGPT, Google AI Overview, Google AI Mode, Gemini, Perplexity and Copilot your buyers' questions every day and shows whether you are mentioned, who is recommended instead, and which sources get cited.