Operated by YaCy Community
YaCy is a distributed, peer-to-peer search engine. Users run their own crawler nodes.
YaCy is a distributed, peer-to-peer search engine. Users run their own crawler nodes.
yacy is a data aggregation crawler. Unlike search bots or AI crawlers, its purpose is typically to collect content for private datasets, price monitoring, or research. Blocking yacy via robots.txt or at the server level has NO negative SEO impact. If you see excessive crawl volume from this bot in your logs, a hard block is recommended.
<code>User-agent: yacy</code> — Matching is case-insensitive. Robots.txt is fetched from the root of each subdomain separately.
yacy is verifiable via reverse-DNS lookup on the crawling IP addresses. You can safely allow it unless you have a specific reason to block (e.g., AI training opt-out or SEO tool visibility).Understanding yacy's purpose helps you decide whether to allow or block it.
yacy. This is the exact string you must use in robots.txt, Nginx, Apache, or Cloudflare firewall rules to target this bot. User-agent matching in robots.txt is case-insensitive, but the string must be spelled correctly. You can verify that a request genuinely comes from yacy by performing a reverse-DNS lookup on the source IP — legitimate bots resolve back to their operator's domain.yacy is verifiable via reverse-DNS lookup on the crawling IP addresses. You can safely allow it unless you have a specific reason to block (e.g., AI training opt-out or SEO tool visibility)./robots.txt file:
User-agent: yacy Disallow: /This instructs yacy not to crawl any path on your site. The Disallow: / directive covers the entire domain including subfolders. To only block specific sections, replace / with the path (e.g.,
Disallow: /blog/). Note: robots.txt is publicly readable — any bot or human can inspect it at yourdomain.com/robots.txt.yacy (case-insensitive grep: grep -i "yacy" /var/log/nginx/access.log). You can also check Google Search Console → Coverage → Crawl Stats for Googlebot variants. For yacy specifically, filter by user-agent in your log analysis tool (GoAccess, AWStats, etc.).User-agent: yacy Crawl-delay: 10(10 second delay between requests).
Disallow: / you can restrict yacy to specific paths:
User-agent: yacy Disallow: /private/ Disallow: /staging/ Allow: /This allows yacy everywhere except the listed paths. Path matching in robots.txt uses prefix matching —
Disallow: /private/ blocks /private/page.html but NOT /public/private/.Crawl-delay: 30 below the User-agent directive in robots.txt.
2. Rate-limit the user-agent via Nginx's limit_req_zone or Apache's mod_ratelimit.
3. Block it outright at Cloudflare WAF with rule: http.user_agent contains "yacy".
4. Use fail2ban to auto-block IPs exceeding request thresholds.