What percentage of websites have an llms.txt file?
In our scan of the 1,000 most-visited websites (Tranco list JZ2VY, 2026-07-01, run 2026-07-05), about 1 in 8 had an llms.txt file published at their domain root: 11.9% of the 653 reachable sites, approximately 78 domains. This is adoption among the most-visited sites on the web, which skews heavily toward large publishers and tech companies. AuditLamp Tranco top-1,000 crawl, 2026-07-05. Full crawler data: auditlamp.com/learn/notes/who-blocks-ai-crawlers-top-1000. Small-business adoption is substantially lower -- not measured in this study.
What is an llms.txt file and what does it do?
An llms.txt file is a plain-text document published at the root of a domain (for example, yourdomain.com/llms.txt). It is meant to give large language models a structured, curated summary of what the site is about and what its most important pages are. The format was proposed in 2024 and adopted informally by some publishers and developers. For what an llms.txt file actually does for AI visibility, the honest answer is: it depends entirely on which AI engine you are asking about.
Google has explicitly stated it ignores llms.txt when deciding what to include in AI Overviews (developers.google.com, July 10, 2026). For other engines such as Perplexity and Claude, there is no published evidence that the file changes citation frequency. It is a cheap experiment with no proven downside, but it is not a ranking lever by itself.
What kinds of sites publish an llms.txt file?
In our Tranco top-1,000 sample, adoption is concentrated among large tech companies, developer tools, API providers, and major publishers. These are organisations that have engineering teams watching the AI space closely. Most small and medium businesses have not published one, and given Google's stated position, there is no urgent reason they must. See our full Tranco top-1,000 AI crawler study for the per-site breakdown and methodology.
The number to watch is not llms.txt adoption; it is whether the engines that do read the file begin citing pages that publish it at measurably higher rates. We have not measured that. If you publish one, note when you did it and check citation frequency 60 to 90 days later.
Does publishing an llms.txt file affect AI search rankings?
For Google: no, per their own documentation. For other engines: unknown. No independent study has shown that llms.txt publication correlates with higher citation rates in Perplexity or Claude answers. The more reliable path to AI citability is structured, specific content with verifiable facts in the opening paragraph -- the same signals our engine checks. See which AI crawlers your site allows or blocks to understand what the crawlers that do read your pages are actually doing.
How do you create an llms.txt file for your website?
The file goes at the root of your domain, publicly accessible at /llms.txt. It typically lists the site's main pages, a short description of what each one covers, and any context about the organisation that a language model should know. There is no official specification; the informal convention is at llmstxt.org. Generate an llms.txt file for your site -- our tool produces a structured file based on your sitemap and page content. Check your site's AI readiness and llms.txt status to see the full picture of how AI engines read your domain.
Cite this data
AuditLamp. "What percentage of websites have an llms.txt file? (2026 data)." Tranco top-1,000 (list JZ2VY, 2026-07-01), n=653 reachable sites, measured 2026-07-05. Published 2026-08-25. auditlamp.com/learn/notes/what-percentage-of-sites-have-an-llms-txt-file. Free to use with attribution.