What is LLMS.txt?

Understanding the proposed standard for helping LLMs access your website content

The Basics

llms.txt is a proposed standard for helping Large Language Models (LLMs) better understand and use content from websites. It's a markdown file that provides AI-readable documentation of your website's structure.

Similar to how robots.txt helps search engines navigate websites, llms.txt gives LLMs a curated map of your most important content.

Why llms.txt Exists

The Problem:

  • LLM context windows are too small to handle most websites in their entirety
  • Converting complex HTML with navigation, ads, and JavaScript is difficult and imprecise
  • LLMs don't know which content on your site is most important or relevant
  • Modern websites with JavaScript-loaded content are hard for AI crawlers to read

The Solution:

llms.txt provides a curated, concise overview of your website's key content in a format that's easy for both humans and LLMs to read. It's specifically designed for inference time - when users are asking LLMs questions about your site.

Format Specification

According to the official specification from llmstxt.org, the format includes:

# Your Site Name
> Brief description of what your site does
Important notes:
- Key point about your site
- Another important note
## Documentation
- [API Reference](url): Description
## Optional
- [Secondary Info](url): Less critical content

Key Elements:

  • H1 Title (#) - Site or project name (required)
  • Blockquote (>) - Concise summary (recommended)
  • Important notes - Critical context (optional)
  • H2 Sections (##) - Organized content areas
  • Markdown links - [Title](URL): Description format
  • Optional section - Secondary information that can be skipped

Current Adoption Status

⚠️ Important: llms.txt is currently a proposed standard. No major LLM provider (OpenAI, Google, Anthropic) has officially confirmed they use these files.

As of mid-2025:

  • Only ~951 websites have published llms.txt files
  • Companies using it include: Anthropic, Vercel, Zapier, Cloudflare, Hugging Face
  • Mainly adopted by developer-focused and SaaS companies
  • Still in "early speculation" phase

Should you use it? It's low effort to implement with potential future benefits. Many companies are experimenting with it as an early adoption strategy.

Best Practices

✓ Do

  • • Use concise, expert-level language
  • • Include brief, informative descriptions
  • • Organize content into logical sections
  • • Link to your most important pages
  • • Use the Optional section for secondary content
  • • Keep the file under 20KB

✗ Don't

  • • Use marketing fluff or superlatives
  • • Include every single page on your site
  • • Use H3, H4 headings (stick to H1, H2)
  • • Leave out link descriptions
  • • Make it too long or complex
  • • Forget to update it regularly

Companion Feature: .md Files

The specification also proposes that pages provide markdown versions by appending.md to the URL:

https://example.com/docs/api.html
↓ append .md
https://example.com/docs/api.html.md

This provides LLMs with clean, structured content without HTML clutter, navigation, or ads.

How to Implement

  1. Generate your llms.txt: Use our tool or write it manually following the spec
  2. Upload to root directory: Place it at https://yourdomain.com/llms.txt
  3. Verify accessibility: Check that the file is publicly accessible
  4. Keep it updated: Regularly review and update as your site changes
Generate Your LLMS.txt Now

Learn More

Official Specification (llmstxt.org)

Complete format specification and examples

Semrush Guide to LLMS.txt

Comprehensive overview and implementation guide

Ahrefs: What Is LLMS.txt?

Critical analysis of adoption and usefulness

LLMS.txt Directory

Browse real examples from companies using llms.txt