Robots.txt Validator

What Is a Robots.txt Validator and Why Do You Need One?

A robots.txt validator checks your robots.txt file for syntax errors, structural issues, and SEO best practices. Since robots.txt controls which search engine and AI crawlers can access your site, even a small syntax error can accidentally block Googlebot, GPTBot, or ClaudeBot from crawling important pages — costing you organic traffic and AI search visibility.

Our free robots.txt checker validates your file instantly, flags errors by severity (critical, warning, info), and specifically checks whether AI crawlers like GPTBot, ClaudeBot, and PerplexityBot are allowed or blocked.

How to Validate Your Robots.txt File (Step-by-Step)

1. Paste or fetch: Either paste your robots.txt content directly or enter your domain URL to fetch it automatically.
2. Run validation: Click "Analyze" to check syntax, directives, and structural rules.
3. Review results: Errors are categorized by severity — fix critical issues first, then warnings.
4. Check AI bot status: Verify whether GPTBot, ClaudeBot, PerplexityBot, and Google-Extended are allowed or blocked.
5. Deploy changes: Save the corrected file as robots.txt in your website root directory.

What Are the Most Common Robots.txt Errors and How to Fix Them?

• Missing User-agent directive: Every rule block must start with a User-agent line. Use User-agent: * for all bots.
• Disallow with no path: An empty Disallow: means "allow everything" — make sure this is intentional.
• Blocking CSS/JS files: Blocking /wp-includes/ or /assets/ prevents Googlebot from rendering your pages correctly.
• Wildcard syntax errors: Using * in paths incorrectly — wildcards are supported in paths but only by Googlebot and compatible crawlers.
• Missing Sitemap directive: Always include Sitemap: https://example.com/sitemap.xml to help crawlers discover your content.
• Conflicting rules: Having both Allow and Disallow for the same path — the more specific rule wins for Googlebot.

Is Your Robots.txt Blocking AI Crawlers Like GPTBot and ClaudeBot?

As AI-powered search engines like ChatGPT, Perplexity, and Google AI Overviews become primary ways users find information, your robots.txt controls whether your content appears in AI responses. Here are the key AI crawler user-agents to know:

• GPTBot — OpenAI's crawler. Blocking it prevents your content from appearing in ChatGPT responses.
• ChatGPT-User — OpenAI's real-time browsing agent used during ChatGPT conversations.
• ClaudeBot — Anthropic's web crawler for Claude AI training and retrieval.
• PerplexityBot — Perplexity AI's crawler for real-time answer generation.
• Google-Extended — Google's AI training crawler (separate from Googlebot for search).
• Applebot-Extended — Apple's crawler for Apple Intelligence and Siri features.

Only 12% of websites explicitly allow AI crawlers like GPTBot in their robots.txt. If you want visibility in AI-powered search results, make sure these bots are not blocked.

What's the Correct Robots.txt Syntax for Different User-Agents?

• User-agent — Specifies which crawler the rules apply to. Use * for all bots.
• Disallow — Tells crawlers not to access specific paths.
• Allow — Explicitly allows access to paths (overrides Disallow for more specific paths).
• Sitemap — Specifies the location of your XML sitemap.
• Crawl-delay — Throttles crawler requests (supported by Bing, not Google).

Example allowing AI crawlers:

User-agent: GPTBot
Allow: /

User-agent: ClaudeBot
Allow: /

User-agent: PerplexityBot
Allow: /

User-agent: *
Disallow: /admin/
Disallow: /private/

Sitemap: https://example.com/sitemap.xml