Outbrain user agent
Operated by Outbrain
Outbrain is the user agent of the Outbrain content recommendation network's crawler.
The Outbrain bot at a glance
- Outbrain is operated by Outbrain and checks landing pages for an advertising platform.
- The robots.txt token for Outbrain is Outbrain.
- Blocking a platform fetcher has no effect on organic search rankings.
- Outbrain robots.txt support: Not documented.
- Recommendation for Generative Engine Optimization (GEO): Allow.
What is Outbrain?
Outbrain reads pages to recommend them in Outbrain widgets on publisher sites.
Publishers that use Outbrain should allow it.
Should you block Outbrain?
Allow Outbrain unless it causes a measurable load problem.
| Effect on search rankings | Blocking a platform fetcher has no effect on organic search rankings. |
|---|---|
| Effect on AI visibility | Blocking breaks the feature the fetcher serves, such as ad approval or feed updates. |
| Follows robots.txt | Not documented |
| Recommendation | Allow |
How to block or allow Outbrain
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 Outbrain is matched case-insensitively. robots.txt alone may not stop Outbrain, so add the Nginx, Apache or Cloudflare rule as well.
robots.txt: block
# Block Outbrain
User-agent: Outbrain
Disallow: /robots.txt: allow
# Allow Outbrain
User-agent: Outbrain
Allow: /robots.txt: partial
# Keep Outbrain out of private areas only
User-agent: Outbrain
Disallow: /wp-admin/
Disallow: /cart/
Disallow: /checkout/
Disallow: /my-account/
Allow: /Nginx
# Nginx: return 403 to Outbrain
if ($http_user_agent ~* "(Outbrain)") {
return 403;
}Apache
# Apache .htaccess: return 403 to Outbrain
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} (Outbrain) [NC]
RewriteRule .* - [F,L]Cloudflare WAF
# Cloudflare > Security > WAF > Custom rule, action: Block
(http.user_agent contains "Outbrain")How to verify real Outbrain traffic
Outbrain publishes no IP list or reverse DNS pattern for Outbrain, 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 Outbrain in your server logs
Search the web server access log for the token. The command below counts Outbrain requests per URL on Nginx or Apache.
grep -i "Outbrain" 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.
Outbrain user agent string
The full user agent Outbrain publishes for Outbrain. Version numbers such as Chrome/W.X.Y.Z change over time, so match the token, not the whole string.
Mozilla/5.0 (Java) outbrainOutbrain FAQ
Outbrain identifies itself with the robots.txt token "Outbrain". A typical request header reads: Mozilla/5.0 (Java) outbrain
Outbrain has not documented how Outbrain treats robots.txt. Add a robots.txt rule and back it with a server rule if the traffic matters to you.
Blocking a platform fetcher has no effect on organic search rankings. Blocking breaks the feature the fetcher serves, such as ad approval or feed updates.
Add two lines to the robots.txt file at the root of each domain and subdomain: "User-agent: Outbrain" followed by "Disallow: /". The token is case-insensitive. Changes can take up to 24 hours to be picked up.
Not reliably. Outbrain publishes no IP list or reverse DNS pattern for Outbrain, so anyone can send the same user agent. Rate-limit unusual volume instead of trusting the name.
Search your server access log for "Outbrain", for example with: grep -i "Outbrain" 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.
