What is llms.txt and why is it important?

llms.txt is a proposed file placed at the root of a website (/llms.txt) in Markdown format to guide LLMs through the site's most important content in a clear, structured way. It exists because HTML pages are often cluttered with ads, navigation, scripts, or dynamic content. LLMs benefit from curated, plain-text summaries that fit their context window limits.

How do I validate my llms.txt file?

You can validate your llms.txt file using our free online validator. Simply enter your website URL (e.g., example.com/llms.txt) or paste your file content directly into the validator. The tool will check for required elements like H1 headers, blockquote summaries, H2 sections, and valid URL formats.

What's the difference between llms.txt and llms-full.txt?

llms.txt contains structured links to your important pages with descriptions, while llms-full.txt is a companion file that includes full plain-text content of documentation. llms-full.txt is useful when LLMs can ingest large context without navigating individual pages, but may exceed context windows.

Is this llms.txt validator free to use?

Yes! Our llms.txt validator is completely free to use. No registration required, no limits on usage. We're committed to helping the web become more AI-friendly.

What are the common errors in llms.txt files?

Common errors include: missing H1 header, missing blockquote summary, no H2 sections, broken or malformed URLs, duplicate URL entries, incorrect Markdown formatting, and files that are too large (>500KB). Our validator checks for all these issues and provides detailed error messages.

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