Free llms.txt validator
Check if your site publishes a proper /llms.txt file so that
ChatGPT, Claude, Perplexity and Gemini can discover your best content.
Audits structure, blockquote summary, H2 sections, link quality,
/llms-full.txt companion and robots.txt compatibility.
No registration required.
Enter any domain — we probe /llms.txt at its root.
Don't have one yet?
Generate one from your sitemap →
What is llms.txt?
llms.txt is a proposed standard by
Jeremy Howard (Answer.AI)
— a plain-text markdown file published at the root of a domain
(https://example.com/llms.txt) that tells large language models
what the site is about and which pages are most useful for them to read.
Cloudflare, Mintlify, Anthropic, Perplexity and hundreds of OSS projects
already ship it. Think of it as robots.txt for LLMs, but with
curated links instead of block rules.
What this validator checks
Reachable at /llms.txt
The file is served at the canonical path with HTTP 200 and text/plain or text/markdown.
Single H1 title
The first line must be # Your project name — exactly one H1.
Blockquote summary
One-line > short summary right after the title gives LLMs instant context.
H2 sections with links
Groups of ## Section name each containing - [Title](url): description bullets.
Link quality audit
Every bullet has a human-readable title, an absolute URL, and an optional description.
Companions & robots
Checks for optional /llms-full.txt and ensures robots.txt doesn't block the file.
Minimal llms.txt example
# FastHTML > The fastest way to build modern Python web apps. FastHTML is a Python framework for building server-rendered web apps with minimal boilerplate. ## Docs - [Quick start](https://fastht.ml/docs/start.md): 5-minute intro - [API reference](https://fastht.ml/docs/api.md): All classes and functions - [Deployment guide](https://fastht.ml/docs/deploy.md): Production recipes ## Examples - [Todo app](https://fastht.ml/examples/todo.md) - [Chat app](https://fastht.ml/examples/chat.md): Real-time with websockets ## Optional - [Changelog](https://fastht.ml/changelog.md) - [Contributing](https://fastht.ml/contributing.md)
Why publish an llms.txt?
Perplexity, ChatGPT Search and Claude with browsing increasingly cite sources they can read quickly. A curated index of your best pages gives them a shortcut to accurate, authoritative content — instead of guessing from rendered HTML.
Full HTML pages with nav, ads and scripts waste LLM context.
llms.txt points to .md or clean pages — a companion
/llms-full.txt can even deliver the entire corpus
in a single request for RAG pipelines.