About

A free tool for the llms.txt community.

llms.txt Checker is a free online validator that helps website owners verify their llms.txt file is correctly structured for large language models. It checks your file against the official llmstxt.org specification proposed by Jeremy Howard (Answer.AI).

What it does

The checker parses your file and validates its structure: the required H1 title, the summary blockquote, optional detail sections, and H2 file-list sections with markdown links. It can also test that every link in your file resolves, and it renders a live preview so you can see how the file is interpreted.

Why llms.txt matters

As AI assistants and agents increasingly read websites at inference time, a well-formed llms.txt file gives them a concise, curated map of your most useful content. It coexists with robots.txt and sitemap.xml but serves a different purpose — helping models understand your site rather than controlling crawler access.

Privacy first

Validation of pasted text runs entirely in your browser. When you check a URL, the request is proxied through a stateless serverless function only to avoid cross-origin restrictions — nothing is stored. See our Privacy Policy for details.

Contact

Questions, feedback, or bug reports? Email info@llmschecker.net or visit our contact page.