llms.txt Validator & Generator
Validate your existing llms.txt or auto-generate one from your sitemap. Based on the llmstxt.org specification.
llms.txt is a standardised file (llmstxt.org) that helps LLM crawlers quickly understand site structure, key sections and important links. Validator checks format correctness (H1, blockquote summary, sections), file size (≤30KB recommended), and presence of key sections.
What is llms.txt?
A Markdown file placed at the root of your website (/llms.txt) that helps AI assistants and LLMs understand your site content without parsing raw HTML.
AI-Readable Format
Plain Markdown that ChatGPT, Claude, Perplexity and other LLMs can parse in a single context window.
Similar to robots.txt
Just like robots.txt guides search crawlers, llms.txt guides AI systems to the right content on your site.
Open Standard
Defined at llmstxt.org — an open, evolving specification supported by the developer community.
Easy to Create
Use the Generate tab above — we parse your sitemap and produce a ready llms.txt file automatically.
llms.txt vs llms-full.txt
- Index of key pages with links
- Compact — fits in one context window
- Fast to generate and validate
- Best for AI navigation and discovery
- Required — start here
- Full content of every page
- Verbose — may exceed context limits
- Useful for deep research queries
- Supplement to llms.txt, not a replacement
- Optional — add later
Common Mistakes
# Project Name
> Short summary after the H1
https://)
## Section headings
Best Practices
[Getting Started Guide](url) is better than just [Page 1](url)
: Brief description for context
llms.txt: https://yourdomain.com/llms.txt to your robots.txt
Why teams trust us
How it works
Enter site URL
Fetch llms.txt file
Get AI-Score and tips
What is llms.txt?
llms.txt is a new open standard proposed by Anthropic. A file at the site root provides AI systems a structured description: what the site is, what content it has, how it's organized.
Structure Validation
Validate llms.txt against spec: H1/H2 headers, link lists, descriptions.
AI Compatibility
Assess how well the file is understood by GPT-4, Claude, Perplexity systems.
llms-full.txt
Check the extended version with full Markdown content of key pages.
Final AI-Score
Numerical score with specific recommendations for improving llms.txt.
Who uses this
Developers
llms.txt validation
SEO
AI search optimization
Marketers
AI answer visibility
Content managers
content structuring
Common Mistakes
Best Practices
Check your llms.txt
Free analysis — improve your site visibility for GPT, Claude, Perplexity.
Sign up freeFrequently Asked Questions
What is llms.txt and why do I need it?
llms.txt is a Markdown file at the root of your website that provides a structured, AI-friendly index of your content. As AI tools like ChatGPT and Claude become primary research tools, having llms.txt helps ensure AI can accurately represent your site — improving discoverability, reducing hallucinations, and giving you control over what AI knows about your project.
How is llms.txt different from robots.txt or sitemap.xml?
robots.txt tells crawlers which pages to skip. sitemap.xml lists all URLs for indexing. llms.txt is different — it's for AI systems reading your content directly. It provides human-readable titles, descriptions, and context that help LLMs understand what your site is about and navigate to its most important content.
Does llms.txt affect SEO?
llms.txt has no direct effect on traditional search engine rankings — Google and Bing do not use it for indexing. Its value is in AI search and conversational tools: as AI-powered search (Perplexity, ChatGPT Search, Claude.ai) becomes more common, having a well-structured llms.txt can improve how your site appears in AI-generated answers.
What score should I aim for in validation?
Aim for Grade A (85–100 points). The most important checks are: H1 heading present, blockquote description, at least one H2 section, and valid absolute URLs. A score of 70+ (Grade B) is perfectly functional. Below 50 means critical structure issues that may prevent AI tools from properly parsing your file.
How often should I update llms.txt?
Update llms.txt whenever you add major new sections, change site structure, or update key documentation. For blogs and news sites, monthly updates are sufficient. Use our Generator — it rebuilds the file from your sitemap in seconds, so keeping it fresh takes minimal effort.
Where exactly should I place the llms.txt file?
Place it at the root of your domain: <code>https://yourdomain.com/llms.txt</code>. Make sure it's publicly accessible (no auth required) and returns Content-Type <code>text/plain</code> or <code>text/markdown</code>. Also consider adding <code>Sitemap: https://yourdomain.com/llms.txt</code> in your robots.txt so AI crawlers can discover it automatically.