llms.txt Validator
Paste your llms.txt and check it against the llms.txt proposal: H1 title, summary, sections, Markdown links and URLs. Free, instant, no signup.
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Privacy and processing
All processing happens in this browser tab. Nothing you open, paste or type is sent to ToolsWebPro servers. The validator checks the text you paste. It does not fetch your live /llms.txt or confirm that linked pages exist.
How to use llms.txt Validator
- 1Paste the contents of your llms.txt file into the validator.
- 2Optionally enter your site URL so relative links can be checked.
- 3Review each reported issue and the explanation of why it matters.
- 4Fix the file, or switch to the generator tab to rebuild it, then validate again.
What you can do
Structure checks
A single H1 title, optional blockquote summary and H2 sections, as the llms.txt proposal describes.
Link checks
Malformed Markdown links, relative URLs and non-HTTPS links.
Explained results
Each check passes, warns or fails, with a note on what to change.
Generator included
Build a new llms.txt in the same tool.
When this tool helps
Checking an llms.txt written by hand or by a CMS plugin before publishing it.
Reviewing a client's llms.txt during an SEO or AI-visibility audit.
Testing changes after adding new docs sections.
About llms.txt Validator
llms.txt is a proposed Markdown file at the root of a site that gives AI tools a short summary and a list of important pages. The proposal asks for an H1 with the site or project name, an optional blockquote summary, and H2 sections containing Markdown link lists. Because there is no official validator, small mistakes are common: two H1 headings, links without a URL, relative paths or plain http:// links. This validator checks those format rules and explains each issue. Be realistic about the result: a valid llms.txt is not proof that any search engine or AI system reads it, and Google does not use llms.txt for ranking. Create or regenerate the file with the llms.txt generator, control AI crawler access separately with the AI robots.txt generator, and see how to fix the Lighthouse llms.txt error.
Check an llms.txt file before you publish it. The validator reports a missing or duplicate H1, malformed Markdown links, relative or non-HTTPS URLs, section structure and file size, with each issue explained. It checks format only: it cannot tell you whether an AI system reads your file. Need to write one first? Switch to the generator tab.
ToolsWebPro provides this tool free with no account required. Each tool explains its supported formats, processing limits and privacy behavior.
Frequently asked questions
- How do I validate an llms.txt file?
- Paste the file contents into the validator. It reports structure and link problems with an explanation for each, so you can fix the file and check it again.
- Is there an official llms.txt validator?
- No. llms.txt is a community proposal without an official validator. This tool checks the format the proposal describes.
- Does a valid llms.txt improve my Google rankings?
- No. Google has not said it uses llms.txt for ranking. A valid file only means AI tools that choose to read it can parse it.
- Does the validator check my live website?
- No. It checks the text you paste and does not fetch your live /llms.txt or test that linked pages load.
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