What is the best free tool to check which AI crawlers my robots.txt blocks?

It depends on what you need. Sona tests the most crawlers (47) with live probes that also catch firewall and CDN blocks. GEO Toolbox covers 34 crawlers with the exact blocking line. Atalaya AI covers 20 crawlers and adds how much of your page an AI crawler can read without JavaScript, a fix prompt for AI-built apps, a 20-site bulk check and Spanish. All three are free without sign-up.

Does robots.txt access mean ChatGPT will cite my site?

No. robots.txt only grants permission to fetch. Being cited depends on what the page says, whether the text is in the HTML, and whether other sites mention you.

Comparison, checked 2026-11-03 · we make one of these tools, and say where others do more

Best free tool to check which AI crawlers your robots.txt blocks

Short answer: for the widest crawler coverage and firewall detection, use Sona. For a fast, clean robots.txt verdict with the exact line, GEO Toolbox. If your site is an app built with Lovable, Bolt or React, or you need Spanish or a check of many client sites at once, Atalaya AI (ours). All three are free with no sign-up.

The five tools side by side

Tool	AI crawlers tested	Exact blocking rule	Firewall / CDN blocks	Text AI can read (no JavaScript)	Sign-up	Extras
Sona	47	yes	yes, live probes vs a normal browser	flags JavaScript-only pages	no	CDN-specific fix, llms.txt, sitemap
GEO Toolbox	34	yes, with line number	separate scan	separate scan	no	grouped by purpose, honest caveats
Atalaya AI (ours)	20	yes	no (tells you where to look: Cloudflare, Vercel, Netlify)	yes: words in the home page HTML, empty app-shell flag	no	fix prompt for Lovable/Bolt/Replit, identity signals, "Does AI know your brand?", 20-site bulk table, CSV, Spanish, MCP server
Centium	21-23	verdict per crawler	no	no	no	clear training / live / index grouping
LLM Pulse	major AI + search bots	line by line	no	separate checker	e-mail required (report by e-mail, newsletter)	blocked paths, sitemap check

Read from each tool's own page on 2026-11-03. Tools change; tell us at hola@atalaya-ai.com if a row is out of date.

Which to use when

"Robots.txt says allowed, but I still don't show up." Use Sona first: its live probes catch a firewall or CDN answering 403 to bots, which no robots.txt reader can see.
"I just need to know which line blocks GPTBot or OAI-SearchBot." GEO Toolbox or Atalaya AI: both name the rule; GEO Toolbox covers more crawlers.
"My site is an app (Lovable, Bolt, Base44, React)." Atalaya AI counts how many words an AI crawler actually gets from your home page HTML and gives you a prompt to paste into your builder. AI crawlers do not run JavaScript, so this is often the real problem (why).
"I manage client sites." Atalaya AI's bulk table checks up to 20 domains at once with a CSV.
"In Spanish, please." Atalaya AI is fully bilingual (atalaya-ai.com/es).

What none of them can tell you

All five check permission. Allowing a crawler does not make ChatGPT, Claude or Perplexity recommend you; that depends on whether your pages answer the question and whether other sites mention you. If you want to see who the AI engines actually recommend for your buyers' questions, and which pages they cite, that is what our paid AI Answer Audit measures.

How we compared

We opened each tool's public page on 2026-11-03 and recorded what it states about crawler count, rules, firewall detection, rendering and sign-up. We did not score them with our own engine, and we listed the cases where another tool is the better choice.

Written with AI. If you spot an error, write to hola@atalaya-ai.com.