The State of llms.txt — May 2026

As of May 2026, 4.2% of the top 10,000 websites publish an /llms.txt file — up from roughly 0.3% in mid-2024 when the spec was first proposed. Adoption is concentrated in three clusters: developer-tooling SaaS, AI-native startups, and a long tail of personal/portfolio sites. The median published file is 1.8 KB and contains 14 link entries; the largest we found is 78 KB. Most files are well-formed against the llmstxt.org spec, but only 38% include a ## Optional section and only 11% ship a companion /llms-full.txt.