llms.txt Validator — Free AI Crawler Readiness Checker
Audit your llms.txt and check AI crawler readiness for a small business website — free, no signup. Paste your file below to see what passes, what's missing, and what to fix next.
How it works
- Open https://yourdomain.com/llms.txt in your browser and copy everything.
- Paste it into the box below.
- Fix anything marked ✕ or !, then check again.
Where do I find my llms.txt?
Open https://yourdomain.com/llms.txt in your browser (swap in your own address) and copy everything you see into the box below.
See a 404 or a blank page? You don’t have one yet — create it with the generator.
Validation results
- File is not empty
- Has an H1 title (# Name)
- Has a one-line summary (> …)
- Has at least one section (## …)
- Has markdown links to pages
- No HTML tags (markdown only)
Paste your llms.txt content to see the checks.
This checks file structure only. It does not guarantee AI citation or ranking — inclusion is decided by each platform.
What llms.txt is, and why audit it
llms.txt is a short markdown file published at your site's root — https://yourdomain.com/llms.txt — that gives AI systems a plain-language map of your business. It follows the llmstxt.org convention: a title, a one-line summary, and sections of markdown links to your priority pages.
Auditing it matters because a broken or malformed file is easy to publish and easy to miss — a missing summary line, a stray HTML tag, links that don't resolve. This validator checks structure only; it cannot confirm live reachability or tell you whether a specific AI system will use the file. Pair it with Express Check, which reads your robots.txt and llms.txt together and reports which AI crawlers can actually reach your site.
What each check verifies
File is not empty
The most basic check — confirms you pasted something to audit. An empty /llms.txt is functionally the same as a missing one.
Has an H1 title
Looks for a level-1 markdown heading naming your business. Without it, an assistant reading the file has no immediate label for who it belongs to.
Has a one-line summary
Checks for a blockquote line directly under the title. This is the sentence most likely to be read first, so keep it accurate and current.
Has at least one section
Confirms a level-2 heading grouping your links, such as Docs or Services. Links without a section read as an unsorted list rather than a map.
Has markdown links to pages
Checks for standard markdown link syntax pointing at your pages. Bare URLs or plain text mentions don't count — the format matters for machine parsing.
No HTML tags
llms.txt is markdown only, not HTML. A pasted <div> or <a href> tag usually means the file was copied from a rendered page instead of exported as plain markdown.
What a passing file looks like
Every check above passes on this example — paste it into the box above, or click "Load example", to see it scored:
# Acme Analytics > Privacy-first analytics for indie developers. Acme helps small teams understand traffic without cookies. ## Docs - [Getting started](https://acme.dev/docs/start) - [API reference](https://acme.dev/docs/api) ## Services - [Pricing](https://acme.dev/pricing) - [Contact](https://acme.dev/contact)
Notice the shape: a title, a one-line summary, then sections of markdown links — no HTML, no tracking parameters, no pages that need a login.
Fixing issues by platform
If a check fails because the file doesn't exist yet, or because a CMS plugin generated something unusual, the fix often lives at the platform level, not just in the text:
On every platform, confirm AI crawlers are not blocked by robots.txt, your CDN or a security plugin — a validated file behind a crawler block still won't be read.
Structure checks passed? Run Express Check — free — to confirm AI crawlers can actually reach your file and the rest of your site.
Run the free checkFrequently asked questions
Is there an official llms.txt validator?
No single vendor-standard tool exists yet — llms.txt is a community convention, not a formal specification. This validator checks your file against the llmstxt.org structure; pair it with Express Check for crawl-access signals.
Does a perfect score mean AI systems will cite my business?
No. A passing score only confirms file structure. Citation still depends on content quality, crawl access and each AI platform's own decisions — no tool can guarantee it.
Can this validator check whether my file is actually reachable online?
No — it checks structure only, from the text you paste in. For live reachability and AI crawler access, run Express Check, which fetches your site directly.
Why does my llms.txt fail the "no HTML tags" check?
Usually because the file was copied from a rendered web page rather than saved as plain markdown. Re-export it as text or rewrite the affected lines using markdown syntax.
I don't have an llms.txt yet — where do I start?
Use the free llms.txt generator to build one from scratch, then paste the result here to confirm the structure before you publish.
Do I need llms.txt at all?
No platform requires it. It's optional GEO preparation that can help some AI systems orient once crawl access already works — not a ranking or citation guarantee.