llms.txt Went From 1.1% to 14.3% of the Top 1 Million Websites Between July 2025 and October 2026

Summary

A year ago, an agency owner who suggested adding llms.txt to a client site would have been early. Most people had never heard of it. Today the same client may already have one without knowing, because their store platform added it.

llms.txt is a short text or markdown file at the root of a website that summarizes the site for AI tools. HTTP Archive started checking for it in July 2025, which lets us track its spread across crawls.

Growth has been steep. Adoption across the top 1 million homepages went from 1.1% to 14.3% in 15 months, roughly 12 times more sites. A single platform rollout explains much of that, but adoption also kept rising on WordPress and among the most visited sites.

What we measured

We queried the HTTP Archive mobile crawl in BigQuery (httparchive.crawl.pages) for seven monthly crawls between July 2025 and October 2026, keeping homepages ranked in the Chrome UX Report top 1 million. HTTP Archive's llms_txt_validation metric records the response to /llms.txt on each site. It first appears in the July 2025 crawl; earlier crawls have no data.

A site counts when /llms.txt returned 200 with a text/plain or text/markdown content type. Platform flags come from HTTP Archive's technology detection on each crawl.

Adoption grew about twelvefold in 15 months

The sample size changes slightly from crawl to crawl, so we compare shares, not raw counts.

Growth was steady through April 2026 at roughly one extra percentage point per quarter. The July 2026 crawl shows a step change, then growth slows again.

One platform rollout created the July spike

We split the trend into Shopify homepages and everything else. Shopify is named here only as an adoption fact.

Outside Shopify, the rate rose from 1.2% to 9.0%, so the trend does not depend on one platform. WordPress sites, where owners or plugins add the file, show the steadiest climb.

The most visited sites are catching up slowly

The two most popular rank buckets grow from a low base.

The top 10,000 went from about 1 in 100 to about 1 in 11 sites. These are mostly hand-made files, since few of these sites run on platforms that publish the file automatically.

What this means

The file is no longer rare, which changes the question for most owners. It is less about being first and more about whether your file is accurate. If your platform created one for you, open it and see which pages it lists. Reviewing that list takes minutes, and it is a standard step in our AI search optimization services.

Growth in adoption does not tell us how much AI tools rely on the file. Use it as a low-cost extra, and spend most of your effort on clear, crawlable pages that answer what buyers ask. For the bigger picture, a free AI visibility audit from our team shows whether AI assistants can find your business and quote it accurately.

Limits

HTTP Archive began recording llms.txt in the July 2025 crawl, so the trend cannot go further back.

The top-1M sample is rebuilt each month from Chrome UX Report data, so some sites enter or leave between crawls.

Platform detection can change between crawls as fingerprints are updated.

We count 200 responses with text content types and do not inspect file contents.

We measured six past crawls plus October 2026 rather than every month, to control query costs.

Frequently asked questions

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