Free tool · No sign-up
llms.txt checker
An llms.txt checker fetches a site’s /llms.txt file and tests it against the format proposed at llmstxt.org: a plain-text file with one H1, a short summary and sections of links. Enter any domain below to see what it finds and what to fix. It is free and needs no account.
7 days free. No card required.
Placton tracks
ChatGPT
Claude
Google AI
Perplexity
Grok
Validate an llms.txt file in seconds
Type a domain and we read its /llms.txt the way an AI tool would, then check it line by line.
Free and without sign-up. We read /llms.txt and /llms-full.txt, nothing else.
What the llms.txt validator checks
The format is a proposal by Jeremy Howard of Answer.AI, published at llmstxt.org (opens in a new tab) in September 2024, not an official standard. So the checker separates the one thing it requires from what it recommends.
Basics
Found at the root of the site
The file has to answer at yourdomain.com/llms.txt with a 200 status. The checker follows redirects, as most readers do, and tells you where they lead.
Basics
Plain text, not a web page
Single-page apps often answer every address with the homepage, so /llms.txt seems to exist but is HTML. The checker catches that and checks the content type.
Required by the format
One H1 title on the first line
The only part the proposal requires: a line such as “# Your brand name”. A second H1 is flagged too.
Recommended
A summary in a blockquote
One or two sentences right below the title, starting with “>”, that say what you do. It is the shortest description of your business a model can find.
Recommended
H2 sections with link lists
Key pages grouped under “##” headings, each written as “- [Name](URL): note”. The checker counts the links and flags list items in another format.
Recommended
Notes on links and full URLs
A note after each link says what the page answers, and a full URL works wherever the file is read. You get a warning when fewer than half the links have a note or any link is relative.
Recommended
A concise size in UTF-8
An index a model can read in one go: the checker warns above 100 KB and reads up to 512 KB. It also flags characters that are not valid UTF-8.
llms.txt best practices
Eight habits that make the file useful to a model and easy to keep up to date, plus a complete example you can copy.
One file per host, at the root. yourdomain.com/llms.txt. A subdomain such as docs.yourdomain.com is another site and needs its own file.
Serve it as text. A static file with a 200 status, the text/plain or text/markdown content type and UTF-8 encoding.
Name and summary first. An H1 with your brand name, then a blockquote with what you sell, to whom and where. Write it the way you would want an assistant to describe you.
Group pages by the questions they answer. Products, pricing, buying help, service, policies. Each link with a short note: “Prices, monthly plans and current offers”.
Link to pages with answers. Pricing, comparisons, guides, policies and contact details. Leave out login, cart, search results and tag archives.
Keep it an index. A few dozen links, not a copy of the site. The proposal suggests Markdown versions of key pages for the full text, and many sites add an llms-full.txt.
Put extras under “## Optional”. The proposal reserves that section for links a reader can skip when space is short: blog, press, history.
Update it when the site changes. New prices, a new product line or a moved page. Run the checker again after each change.
example.com/llms.txt
# Example Bike Co. > Example Bike Co. sells electric city bikes online across the US and runs a repair shop in Austin, Texas. Free shipping on orders over $500 and 30-day returns. We answer questions about choosing an e-bike, financing, servicing and warranty claims. ## Bikes - [City e-bikes](https://example.com/bikes/city): Models, range, weight and prices - [Folding e-bikes](https://example.com/bikes/folding): Compact models for commuters ## Buying help - [Pricing and financing](https://example.com/pricing): Prices, monthly plans and current offers - [How to choose an e-bike](https://example.com/guides/choose): Range, motor and frame size explained - [Shipping and returns](https://example.com/shipping): Delivery times, costs and the return policy ## Service - [Repair shop in Austin](https://example.com/repair): Services, prices and opening hours - [Warranty](https://example.com/warranty): What the 2-year warranty covers and how to claim ## Optional - [Blog](https://example.com/blog): Riding tips and product news - [About us](https://example.com/about): Company history and team
What an llms.txt file can and cannot do
Some AI companies publish llms.txt files for their own developer documentation, but none of the five AI platforms Placton tracks has said that it reads llms.txt to decide which brands to mention or which pages to cite. Treat the file as cheap and useful, not as a ranking switch.
When ChatGPT, Perplexity or Claude answer with web search, they find pages through search and read them. What weighs more is whether their crawlers may read your site, whether your text is in the HTML and whether other sites mention you. The AI crawler checker covers the first, and the free 18-point GEO audit the second.
See whether AI recommends you
The only way to know is to ask. Placton sends the questions your customers ask to ChatGPT, Google AI Overviews, Claude, Perplexity and Grok, and shows when they name your brand or cite your pages. Enter your website to start.
What the trial includes
Your llms.txt is one input. The trial shows the output: what five AI platforms say when your customers ask.
7 days free, no card. Sign up with your email or Google. When the trial ends, tracking stops and nothing is charged.
Up to 10 prompts. We suggest prompts and competitors from your website, and you edit the list before the first run.
All five AI platforms on day one. ChatGPT, Google AI Overviews, Claude, Perplexity and Grok answer your prompts as soon as your email is confirmed.
ChatGPT and Google AI again every day while you keep visiting your dashboard. Claude, Perplexity and Grok are asked once, at sign-up.
One “Run now” and the 18-point site audit. It includes the llms.txt check, and anyone can run it free in our GEO audit tool.
On paid plans only: team invites and the weekly email summary with alerts.
* On paid plans. ChatGPT is read on chatgpt.com in every country Placton tracks except Venezuela and Puerto Rico, where it is asked weekly through its API.
Placton Starter
Track 20 prompts on 5 AI platforms
$59/ month (USD)
Or $602 billed yearly · save $106
Start your 7-day free trial7 days free. No card required.
- Up to 20 prompts, about 1,440 answers a month
- ChatGPT, Google AI Overviews, Claude, Perplexity, Grok
- ChatGPT and Google AI every day*, the other three every week
- Competitor ranking (up to 25 rivals) and every cited URL
- Weekly insights, plus an email summary with alerts
- 18-point AI-readiness site audit
- Up to 2 team members
Need more prompts? Growth is $129 a month for 75 and Scale $299 for 250. Compare all plans
llms.txt checker FAQ
About Placton itself? Read the full FAQs or see every plan and price.
What is an llms.txt file?
A plain-text file written in Markdown at the root of a website (/llms.txt) that gives language models a short summary of the site and links to its key pages. It was proposed at llmstxt.org in September 2024 as a companion to robots.txt and sitemap.xml.
Do ChatGPT, Claude or Perplexity read llms.txt?
None of them has said publicly that it uses llms.txt to choose which brands to mention or which pages to cite. A model can read the file when it visits your site, like any other page, but that does not make it a ranking signal.
Publish one because it is cheap and harmless, and judge the results by what the AI actually says about you.
Is llms.txt the same as robots.txt?
No. robots.txt tells crawlers what they may fetch, and the documented AI crawlers follow it. llms.txt only suggests what to read and adds no rules. If robots.txt blocks an AI crawler, a perfect llms.txt will not help it.
Where does llms.txt go, and do subdomains need one?
At the root of each host: yourdomain.com/llms.txt. A subdomain such as docs.yourdomain.com is a separate site and needs its own file. If www redirects to the bare domain, make sure /llms.txt follows the same redirect.
What is llms-full.txt?
A companion file some sites publish with the full text of their key pages in one place. The proposal itself suggests Markdown versions of each page (the same address with .md added). Both are optional: the checker tells you whether llms-full.txt exists but does not grade it.
Why does the checker say my llms.txt is a web page?
Your server answered /llms.txt with HTML, usually the homepage. Single-page apps and some hosting setups do that for any address they do not know. Upload llms.txt as a static file and serve it as text/plain or text/markdown.
Is the llms.txt checker free?
Yes, with no account, on your site or anyone else’s. Each connection gets 10 checks an hour and 30 a day, and neither the domain nor the file is stored.
Your llms.txt is in place. Is your brand in the answers?
Enter your website and Placton drafts the prompts your customers would ask and the competitors to watch. You edit both, and the first answers arrive the same day.
7 days free. No card required.