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llms.txt Validator

Paste your file. Get instant, line-level feedback against the spec.

Confirm your llms.txt has a valid title, summary, and link sections before AI tools read it. Runs entirely in your browser.

Paste your llms.txt
Result

Paste or upload an llms.txt file to check it against the spec.

Open in the generator to fix
Spec rule checks

Verifies the required H1 title, the summary blockquote, well-formed link lists, valid URLs, and the placement of the Optional section.

Line-level findings

Each warning and error points at the line so you can fix the file fast instead of guessing.

Fix in the generator

One click hands your file to the llms.txt generator so you can repair structure with a form and live preview.

Private by default

Validation runs entirely in your browser. Your file is never uploaded to a server.

Need to build one from scratch? Use the llms.txt generator with sitemap import.

Frequently asked questions

What does the llms.txt validator check?

It checks the structure defined by the llms.txt spec: a required H1 title, a recommended summary blockquote, link list items in the form - [name](url): note, valid URLs, duplicate links, and whether the special Optional section is placed last. Each result is marked as a pass, a warning, or an error.

Is an llms.txt with warnings still valid?

Yes. The only strictly required element is the H1 title, so a file with no errors is valid. Warnings flag things that are recommended for quality — like a missing summary or a malformed link line — but they do not make the file invalid.

Is the validator free?

Yes. No sign up, no limits. Paste or upload your file and you get instant feedback. Nothing is stored.

Where should llms.txt live?

At the root of your site, served at https://yoursite.com/llms.txt as text/plain. The validator works on the file contents regardless of where you host it.

How do I fix the issues it finds?

Use the 'Open in the generator' link. It loads your file into the llms.txt generator, where a structured form and live preview make it easy to correct the title, summary, and link sections, then export a clean file.

FOR TEAMS THAT DOCUMENT CODE

Keep the docs behind your llms.txt accurate

Moxie Docs connects to your GitHub repositories, generates searchable documentation, catches drift on every merge, and serves that context to AI coding agents over MCP — so the pages your llms.txt links to never go stale.

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