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LLM.txt Checker & LLMS.txt Validator

Instantly check whether your website has an llms.txt file, validate its structure and quality, and get actionable recommendations to improve your AI discoverability — free, no signup required.

Supports example.com, https://example.com, or https://www.example.com

✓ No account needed✓ Real-time server-side check✓ 7-point validation✓ Instant quality score
Background

What is llms.txt?

A plain-text file that tells LLMs what your website is about — and why that matters in an AI-first world.

llms.txt is a plain-text file placed at the root of your website (e.g. https://example.com/llms.txt) that provides structured context about your site specifically for large language models.

As AI assistants like ChatGPT, Gemini, and Perplexity increasingly answer user questions by drawing on web content, site owners need a clear, machine-readable way to communicate what their site is about, what its key pages are, and how its content should be understood.

llms.txt is inspired by robots.txt — a decades-old convention that tells crawlers how to navigate a site. But where robots.txt restricts or permits access, llms.txt actively explains context.

llms.txt vs robots.txt

robots.txt

Controls crawler access — what to index or ignore

Audience: Search engine crawlers

llms.txt

Explains site context and structure for LLMs to understand

Audience: AI language models & retrieval systems

AI Discoverability

Why llms.txt Matters for SEO and AI Discovery

🔍

Structured Guidance for LLMs

LLMs don't crawl the web the way search engines do. A clear llms.txt gives AI systems a direct, curated summary of your site — reducing the chance of misrepresentation or omission in AI-generated answers.

📡

AI Retrieval Workflows

AI-powered search tools increasingly use retrieval-augmented generation (RAG) to ground answers in web content. A well-structured llms.txt can act as a first-pass context layer for these pipelines.

🏗️

Complementary to Technical SEO

llms.txt is not a replacement for strong content, schema markup, or authoritative backlinks. Think of it as an additional signal layer that can only help — combined with, not instead of, solid SEO fundamentals.

An honest perspective on llms.txt for SEO

We won't overclaim: there is no confirmed evidence that llms.txt directly improves Google rankings or guarantees inclusion in AI-generated answers. What it can do is make your site's purpose and structure more legible to AI systems — which is increasingly how people find and evaluate information. Implement it as a low-effort, forward-looking best practice alongside your core SEO strategy.

Implementation

How to Create and Implement an llms.txt File

A practical, step-by-step guide to adding llms.txt to your website.

01

Create a plain text file

Create a new file called llms.txt. It should be UTF-8 encoded plain text — not HTML, not a Word document, not JSON.

02

Write a site description

Start with a clear # heading and a short paragraph explaining what your site is, who it's for, and what topics it covers. Write naturally — LLMs understand plain English.

03

Add key pages with context

List your most important pages as full URLs with a brief annotation explaining what each page covers. Use ## headings to group pages by category.

04

Place it at your root domain

Upload the file so it's accessible at https://yourdomain.com/llms.txt. Configure your server to serve it with Content-Type: text/plain.

05

Validate with this tool

Run your domain through this checker to confirm the file is accessible, well-structured, and passes all validation checks.

Example llms.txt

# Example Company — AI Visibility & Analytics Platform

> We help brands understand and optimise how AI systems represent them.
> Our platform tracks Share of Voice across ChatGPT, Gemini, and Perplexity.

## Key Pages

- [Home](https://example.com/): Overview of our platform and capabilities
- [Features](https://example.com/features): Full list of tracking features and integrations
- [Pricing](https://example.com/pricing): Plans and pricing for teams of all sizes
- [Blog](https://example.com/blog): Research and guides on AI visibility and GEO

## About

Founded in 2025. Based in Europe. Focused on the intersection of AI and brand discoverability.

✗ Common Mistakes

  • —Serving as HTML instead of text/plain
  • —Placing behind authentication
  • —Leaving it empty or too short
  • —Including broken or relative URLs
  • —Keyword stuffing instead of natural language

✓ Best Practices

  • —Use markdown headings for clear structure
  • —Write naturally in complete sentences
  • —Include full absolute URLs only
  • —Keep it concise — quality over quantity
  • —Update it when your site's focus changes
About This Tool

How This llms.txt Validator Works

What we check — and what pass, warning, and fail mean.

🌐

File existence

We fetch /llms.txt from your domain's root and confirm it returns HTTP 200.

🔒

Accessibility

We verify the file is publicly accessible without authentication or redirects that block access.

📄

Content-Type

We check that the file is served as text/plain — the recommended MIME type for llms.txt.

📏

Content length

We flag files that are empty or too short to be useful, as a guideline rather than a hard rule.

🏗️

Structure

We look for markdown headings (# and ##) that indicate the file is logically organised.

🔗

Valid URLs

We scan for URLs and flag any that appear malformed or invalid.

📝

Site description

We detect whether the file contains contextual description content vs just a list of links.

🚫

Duplicate lines

We flag repeated lines that may indicate a copy-paste error or poor file hygiene.

✅

Readable content

We ensure the file is clean, human-readable text without binary or corrupted characters.

Understanding Results

✓ Pass

This check meets best practice. No action needed.

⚠ Warning

Recommendeded improvement. The file still works, but this is worth addressing.

✗ Fail

Critical issue that should be fixed. The file may not be readable by LLMs.

FAQ

Frequently Asked Questions About llms.txt

What is llms.txt?+
llms.txt is a plain-text file placed at the root of a website (e.g., https://example.com/llms.txt) that provides structured information about the site specifically intended for large language models (LLMs). Think of it as a site-summary for AI — describing what the site is about, what key pages exist, and how AI systems should interpret or reference its content.
What is an llms.txt file?+
An llms.txt file is a simple markdown-formatted text document that site owners can publish to communicate structured context to LLMs. It typically includes a site description, links to key pages, and guidance on how the content should be referenced. The format is inspired by the long-established robots.txt convention and is increasingly discussed as a best practice for AI-era web publishing.
How do I create an llms.txt file?+
Creating an llms.txt file is straightforward: create a plain text file, write a clear description of your site using markdown formatting, list your most important pages as URLs with context, add any relevant guidance for AI systems, and publish it at https://yourdomain.com/llms.txt. Serve it with Content-Type: text/plain. A well-structured llms.txt includes headings (#, ##), a brief intro paragraph, and annotated URLs.
How do I use llms.txt?+
Once published, your llms.txt file can be discovered and read by LLM crawlers and AI systems that choose to respect it. The file is meant to complement your existing content — not replace good writing, structured data, or technical SEO fundamentals. Some AI-powered search tools and retrieval systems may use it as part of their indexing workflows.
Will llms.txt help my SEO?+
llms.txt is not an SEO ranking signal in the traditional sense — Google Search has not announced that it uses llms.txt as a ranking factor. However, it may help with AI discoverability in LLM-powered search tools, and it contributes to a well-organised, machine-readable web presence that can only help over time. Think of it as complementing — not replacing — strong technical SEO, good content, and authoritative backlinks.
How to get indexed by LLMs through an llms.txt file?+
While there is no guaranteed way to force LLM indexing, a well-formatted llms.txt file can make it easier for AI systems to understand your site's purpose and key resources. Best practices include: keeping the file publicly accessible, using clear markdown structure, including annotated links to important pages, writing in plain natural language, and avoiding duplicate or empty content. Combining llms.txt with strong source authority (being cited in credible sources) remains the most reliable path to LLM visibility.
Does Google use llms.txt?+
As of early 2026, Google has not officially announced support for or reliance on llms.txt in its search ranking algorithms. Google Search continues to primarily use its established crawling and indexing processes. However, llms.txt is maintained as a forward-looking best practice for AI era discoverability, particularly relevant for AI Overviews, Gemini, and other LLM-powered surfaces.
Does ChatGPT use llms.txt?+
OpenAI has not publicly confirmed that ChatGPT or its crawlers use llms.txt files for ranking or citation decisions. However, as AI assistants evolve to incorporate real-time web retrieval, structured files like llms.txt may become more relevant. Having one in place is a low-effort, forward-looking practice that can only help as the ecosystem matures.
Does llms.txt work?+
The effectiveness of llms.txt depends on whether specific LLM systems choose to use it. The standard is still evolving — think of it like the early days of robots.txt, which gained widespread adoption over time. There is genuine community momentum and adoption among AI-forward site owners. The practical value today is primarily about signalling intent and making content structure clearer to AI-driven retrieval systems.
Where should I place llms.txt on my site?+
Your llms.txt file should be placed at the root of your domain, accessible at https://yourdomain.com/llms.txt — similar to robots.txt. It should be publicly accessible without authentication, served as plain text, and ideally cached efficiently to ensure fast loading for crawlers.
What should an llms.txt file include?+
A well-structured llms.txt typically includes: (1) a clear site description in the first paragraph, (2) markdown headings to separate sections, (3) annotated links to your most important pages, (4) context about your site's purpose, audience, and key topics, and (5) optionally, guidance on how AI should treat your content. Keep it concise, honest, and machine-readable. Avoid keyword stuffing — write for machines that understand natural language. For large sites, you can also publish a more detailed llms-full.txt alongside your standard llms.txt — llms-full.txt is an extended version intended for AI systems that can process longer documents.
Which AI crawlers check llms.txt?+
The llms.txt standard is still evolving and not all AI crawlers explicitly seek out or use llms.txt files. However, the following AI-associated crawlers are known to index web content and may respect llms.txt as adoption grows: GPTBot (OpenAI / ChatGPT), ClaudeBot and claude-web (Anthropic / Claude), PerplexityBot (Perplexity AI), Bytespider (ByteDance / TikTok search), CCBot (Common Crawl, used in LLM training), and AI2Bot (Allen Institute for AI). For search-engine AI Overviews, Googlebot remains the primary crawler — llms.txt does not replace robots.txt for controlling these crawlers, but serves as a complementary layer of intent signalling.

Check Another Domain

Run the llms.txt validator on any website — a competitor, a client site, or your own domain after making improvements.

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