Free llms.txt Validator & Syntax Checker
Verify your website's /llms.txt file. Ensure your content is properly ingested by ChatGPT Search, Perplexity, Claude, and Google AI Overviews.
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Read the llms.txt Standard Guide
Why do modern AI search engines require an llms.txt file? Learn the technical design choices behind dual-mode index vs full corpus architectures.
Frequently Asked Questions
What is an llms.txt file and why do AI search engines need it?
An llms.txt file is a standardized markdown manifest placed in your website's root directory (e.g., https://yourdomain.com/llms.txt). It provides generative AI crawlers (like OpenAI SearchBot, PerplexityBot, and Googlebot) with a structured, noise-free roadmap of your primary documentation and brand authority assets.
What are the common syntax mistakes in llms.txt?
Common mistakes include missing the top-level # Title, omitting the executive blockquote summary (> description), serving HTML instead of markdown, or returning 404 errors. Our validator inspects all these criteria in one pass.
Is this validator tool completely free?
Yes. GeoFN provides this online validator 100% free with no signup or API key required. You can also run audits locally via our open-source CLI: npx open-geo audit yourdomain.com.