ICC-Crawler user agent
Operated by NICT
ICC-Crawler is the crawler of Japan's NICT, reported as collecting data for AI technologies that may be shared with third parties.
The ICC-Crawler bot at a glance
- ICC-Crawler is operated by NICT and collects public web pages that may be used to train AI models.
- The robots.txt token for ICC-Crawler is ICC-Crawler.
- Blocking an AI training crawler has no effect on Google or Bing rankings.
- ICC-Crawler robots.txt support: Yes.
- Recommendation for Generative Engine Optimization (GEO): Your choice.
What is ICC-Crawler?
ICC-Crawler gathers pages for NICT research, and the data can be provided to other organizations, including companies.
Public registries report that it follows robots.txt.
Should you block ICC-Crawler?
Blocking ICC-Crawler is a business decision: it protects your content but can lower how well AI products know your brand.
| Effect on search rankings | Blocking an AI training crawler has no effect on Google or Bing rankings. |
|---|---|
| Effect on AI visibility | Blocking keeps your future pages out of that company's training data, so its models may know less about your brand over time. It does not remove you from that company's AI search, which uses a separate bot. |
| Follows robots.txt | Yes |
| Recommendation | Your choice |
How to block or allow ICC-Crawler
Put the robots.txt rule in the file at the root of every domain and subdomain, for example https://example.com/robots.txt. The token ICC-Crawler is matched case-insensitively.
robots.txt: block
# Block ICC-Crawler
User-agent: ICC-Crawler
Disallow: /robots.txt: allow
# Allow ICC-Crawler
User-agent: ICC-Crawler
Allow: /robots.txt: partial
# Keep ICC-Crawler out of private areas only
User-agent: ICC-Crawler
Disallow: /wp-admin/
Disallow: /cart/
Disallow: /checkout/
Disallow: /my-account/
Allow: /Nginx
# Nginx: return 403 to ICC-Crawler
if ($http_user_agent ~* "(ICC\-Crawler)") {
return 403;
}Apache
# Apache .htaccess: return 403 to ICC-Crawler
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} (ICC\-Crawler) [NC]
RewriteRule .* - [F,L]Cloudflare WAF
# Cloudflare > Security > WAF > Custom rule, action: Block
(http.user_agent contains "ICC-Crawler")How to verify real ICC-Crawler traffic
NICT publishes no IP list or reverse DNS pattern for ICC-Crawler, so the user agent cannot be verified. Anyone can send the same string. Rate-limit unusual volume instead of trusting the name.
How to find ICC-Crawler in your server logs
Search the web server access log for the token. The command below counts ICC-Crawler requests per URL on Nginx or Apache.
grep -i "ICC-Crawler" access.log | awk '{print $7}' | sort | uniq -c | sort -rn | head -20For a full report per AI bot, upload the log to the AI Log File Analyzer, a free tool by Justin Hà.
ICC-Crawler FAQ
ICC-Crawler uses the robots.txt token "ICC-Crawler". NICT does not publish a full user-agent string, so match the token inside the User-Agent header.
Yes. NICT states that ICC-Crawler follows robots.txt rules written for the "ICC-Crawler" token.
Blocking an AI training crawler has no effect on Google or Bing rankings. Blocking keeps your future pages out of that company's training data, so its models may know less about your brand over time. It does not remove you from that company's AI search, which uses a separate bot.
Add two lines to the robots.txt file at the root of each domain and subdomain: "User-agent: ICC-Crawler" followed by "Disallow: /". The token is case-insensitive. Changes can take up to 24 hours to be picked up.
Not reliably. NICT publishes no IP list or reverse DNS pattern for ICC-Crawler, so anyone can send the same user agent. Rate-limit unusual volume instead of trusting the name.
Search your server access log for "ICC-Crawler", for example with: grep -i "ICC-Crawler" access.log. The AI Log File Analyzer by Justin Hà counts visits per AI bot from an uploaded log file.
Sources: Public bot registry. Last reviewed by Justin Hà.
See which of these bots actually reach your website
The AI Log File Analyzer by Justin Hà counts visits from GPTBot, ClaudeBot, PerplexityBot and other AI crawlers in your server log, for free. The GEO Technical Package sets up robots.txt, llms.txt and crawler access for AI search.
