Guide

How to test your llms.txt

Published: 2026-06-25

A file that looks fine can still be malformed or point at dead pages. Here's what to verify before — and after — you publish.

1. Structure

Confirm the spec basics: exactly one # H1 title, a blockquote summary right below it, and ## sections that contain Markdown link lists. Multiple H1s or empty sections are the most common structural mistakes (see common llms.txt mistakes).

2. Link reachability

This is the check most tools skip. Every linked URL should actually resolve — a perfectly formatted file that points at 404s wastes a crawler's budget and undermines trust. Request each link and look for broken or redirecting ones.

3. Best practices

• Absolute https:// URLs (not relative or http://).
• A short : description after each link.
• Served as Content-Type: text/plain; charset=utf-8.

Manual vs automated

You can eyeball the structure and click links by hand, but reachability across dozens of URLs is tedious and easy to get wrong. An automated check does it in seconds and scores the result.

The fast way

Paste your domain (or the raw text) into the validator. It checks structure, fetches every linked URL concurrently, applies the best-practice rules above, and returns a 0–100 score with a prioritized, fixable list of findings. Re-run it whenever you change the file.

Keep reading

• Common llms.txt mistakesThe llms.txt errors we see most — multiple H1s, no summary, broken or relative links, wrong content type, bloated files — and exactly how to fix each one.
• Does llms.txt help SEO?llms.txt won't change your Google rankings directly. Here's what it actually does, why it matters for AI answers, and when it's worth your time.

Validate your llms.txt →