Free llms.txt Validator — Check Your AI File for Compliance | GrandRanker
Free Tool

Free llms.txt Validator

Check your llms.txt file against the official spec. Validates 12 rules including H1 structure, summary blockquote, sections, link format, and absolute URLs. Get a score, fixes, and an embeddable verification badge.

Auto-checks /llms.txt and /llms-full.txt. Cached 24h. No signup.

What is llms.txt?

llms.txt is an emerging open standard for helping LLMs understand your website. It is a single Markdown file at the root of your domain that lists your most important pages in a curated, AI-friendly format.

Think of it as the AI-era equivalent of sitemap.xml, but designed for ChatGPT, Perplexity, and Claude instead of Googlebot. Major companies including Anthropic, Stripe, and Mintlify already publish llms.txt files.

The validator runs 12 spec rules against your file and outputs a score, line-by-line issues, and an embeddable verification badge.

Sample llms.txt structure
# GrandRanker

> AI-powered SEO platform that automates keyword research, content creation, optimization, and publishing to grow organic traffic on auto-pilot.

## Docs

- [Homepage](https://grandranker.com): GrandRanker overview and features
- [Pricing](https://grandranker.com/pricing): Plans starting from $49/month
- [Platform](https://grandranker.com/platform): CMS integrations and capabilities

## Free Tools

- [SEO Audit](https://grandranker.com/free-tools/seo-audit): Free comprehensive SEO audit
- [GEO Score Checker](https://grandranker.com/free-tools/geo-score-checker): AI search readiness score
- [Schema Generator](https://grandranker.com/free-tools/schema-markup-generator): JSON-LD schema markup

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- [Affiliate Program](https://grandranker.com/affiliate-program): 30% recurring commission
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Frequently asked

Everything to know about llms.txt and validation.

What is llms.txt?

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llms.txt is an emerging open standard (proposed by Jeremy Howard) that helps AI engines like ChatGPT, Perplexity, and Claude understand your website structure. It is a Markdown file at /llms.txt that lists key URLs in a curated format optimized for LLM consumption.

Is llms.txt the same as robots.txt or sitemap.xml?

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No. robots.txt tells crawlers what they can and cannot access. sitemap.xml is an XML list of all URLs for traditional search engines. llms.txt is a curated, human-readable Markdown summary of the most important content for AI systems. The three complement each other.

What does this validator check?

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The validator runs 12 checks against the llms.txt spec: H1 header presence and content, summary blockquote, H2 sections, link format, absolute URLs, Optional section, file size, encoding, empty headings, and more. It returns a 0-100 score plus per-check pass/warn/fail details.

Where should I put my llms.txt file?

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Place it at the root of your domain: yoursite.com/llms.txt. For longer documentation, you can also publish yoursite.com/llms-full.txt. The validator checks both locations automatically.

Do AI engines actually read llms.txt?

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Adoption is growing. Anthropic, OpenAI, and Perplexity have all published support. Major sites including Anthropic, Stripe, Mintlify, and Vercel publish llms.txt files. Even if not every engine reads it today, getting ahead of the curve costs nothing.

How do I generate an llms.txt if I do not have one?

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A llms.txt generator is on the GrandRanker roadmap. For now, you can write one manually following the spec at llmstxt.org. The example below shows the structure.