Does the llms.txt file work? It certainly seems to make sense. However, tracking adoption has been difficult.
Behold! Our adoption statistics!
At llmstxt.studio we have taken the top one million websites in the world and begun tracking how many of them have adopted llms.txt in some form. Every domain is checked again on a schedule: weekly if it publishes a file, monthly if it does not, and daily while a file is changing. We can therefore also track the adoption rate of these websites over time.
1,000,642
domains checked
76,947
publish an llms.txt
7.64%
adoption across the ranked sample
35.5%
of adopters also publish llms-full.txt
Counts from the llms.txt Registry on 13 September 2026, 22 days into observation. Nothing is extrapolated. The live page updates as the scanner runs.
We don't believe anyone else is tracking llms.txt adoption at this scale yet. Rankability counts the Tranco top 1,000 and top 10,000 each month, and where the two overlap the numbers land in the same range. Nobody we know of is watching a million domains and keeping the history. So we wanted to lead the way and be first.
This was difficult
Tracking and maintaining a list of one million websites and grading them is quite a major undertaking. The initial sweep is the expensive part. After that the cost is set by how often we revisit the roughly half of the web that will never have a file, which is why those domains get a monthly look rather than a daily one.
As a result of this work, we hope we and our users alike can track llms.txt adoption going forward. We have seen new ripples of interest since the initial llms.txt announcement.
Google is coming round
In May 2026, Google shipped Lighthouse 13.3 with a new Agentic Browsing category, and it includes an llms.txt check. The audit looks for the file at the domain root and fails if the server errors when asked for it. Lighthouse's own explanation is that without llms.txt, "agents may spend more time crawling the site to understand its high-level structure and primary content."
This from a company that was initially reluctant. Google Search's guidance still says you do not need llms.txt for its generative AI features, and John Mueller once compared the file to the keywords meta tag. Chrome's Lighthouse team now treats it as part of agentic readiness. Google is coming increasingly over to the idea that llms.txt holds future promise, even if the search side has not said so yet.
Sources
Lighthouse llms.txt audit documentation, Chrome for Developers. Google adds llms.txt check to Chrome Lighthouse, Search Engine Land, 20 May 2026. Google's llms.txt guidance depends on which product you ask, Search Engine Journal.
Track it yourself
You can begin tracking this data today on the llms.txt adoption statistics page, or look up any single domain in the registry to see what it publishes and how that has changed. If you want to see where your own site stands, sign up free and run the audit.
Questions
How many websites have an llms.txt?
As of 13 September 2026, 76,947 of the 1,000,642 domains we have probed publish one, which is 7.64% of the ranked sample. The live figure is on the adoption statistics page.
How often is each domain rechecked?
Weekly if it publishes a file, monthly if it does not, and daily while a file is changing. Every figure is a count from a real probe, not an estimate.
Where does the list of one million websites come from?
The Tranco ranking of top domains, loaded once and revisited on a schedule. Adoption is computed over that ranked sample only, never over domains people chose to audit, so self-selection cannot inflate it.