If you're building a website and want it to be LLM-ready, you're probably starting to hear about llms.txt a new Markdown-based standard that helps LLMs understand your site better by skipping messy HTML, ads, and JavaScript.
But writing a valid llms.txt isn't always obvious or straightforward.
That's why I built llmstxtvalidator.dev
https://llmstxtvalidator.dev
It’s a free, browser based tool that validates your llms.txt and llms-full.txt files in seconds.
No signup. No config. Just paste or fetch, and get results.
What the validator does:
• Checks if your llms.txt starts with a proper # title and summary
• Parses all sections, like Documentation, Blog, API etc.
• Validates link syntax, structure, and description
• Warns about malformed Markdown, missing elements, duplicates or large file sizes
• Supports both pasted text and live URLs (like https://yoursite.com/llms.txt)
Why it matters:
LLMs like ChatGPT, Claude, Gemini and others are beginning to crawl the web with new logic.
They prefer structured, concise, semantic content.
llms.txt is your site’s “AI-facing map” — a guide for how LLMs should interpret your content.
This is part of what people now call GEO (Generative Engine Optimization), and it’s likely going to matter more over time.
Try the validator here:
https://llmstxtvalidator.dev
You can also embed a badge in your README or docs to show your site is LLM-ready:
Validated by llmstxtvalidator.dev
Built with Next.js, Tailwind CSS, and zero marketing budget.
If you're working on anything related to LLMs, I'd love to hear from you.
Feedback, PRs, or shoutouts are all welcome.
Let’s make the web more readable for machines.
Top comments (1)
Happy to answer any questions about llms.txt or how LLMs are indexing content