Slackbot user agent
Operated by Slack
Slackbot is the fetcher Slack uses to expand links into previews inside Slack messages.
The Slackbot bot at a glance
- Slackbot is operated by Slack and reads page titles, descriptions and images to build link previews.
- The robots.txt token for Slackbot is Slackbot.
- Blocking a social preview bot has no effect on search rankings.
- Slackbot robots.txt support: Yes.
- Recommendation for Generative Engine Optimization (GEO): Allow.
What is Slackbot?
Slackbot-LinkExpanding visits a link posted in Slack to read its title, description and image for the unfurled preview.
Slack documents its robots on its own API site, including Slack-ImgProxy for images.
Should you block Slackbot?
Allow Slackbot unless it causes a measurable load problem.
| Effect on search rankings | Blocking a social preview bot has no effect on search rankings. |
|---|---|
| Effect on AI visibility | No direct effect on AI answers, but shared links lose their title, image and description, which usually lowers clicks from social and chat apps. |
| Follows robots.txt | Yes |
| Recommendation | Allow |
How to block or allow Slackbot
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 Slackbot is matched case-insensitively.
robots.txt: block
# Block Slackbot
User-agent: Slackbot
Disallow: /robots.txt: allow
# Allow Slackbot
User-agent: Slackbot
Allow: /robots.txt: partial
# Keep Slackbot out of private areas only
User-agent: Slackbot
Disallow: /wp-admin/
Disallow: /cart/
Disallow: /checkout/
Disallow: /my-account/
Allow: /Nginx
# Nginx: return 403 to Slackbot
if ($http_user_agent ~* "(Slackbot)") {
return 403;
}Apache
# Apache .htaccess: return 403 to Slackbot
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} (Slackbot) [NC]
RewriteRule .* - [F,L]Cloudflare WAF
# Cloudflare > Security > WAF > Custom rule, action: Block
(http.user_agent contains "Slackbot")How to verify real Slackbot traffic
Slack publishes no IP list or reverse DNS pattern for Slackbot, 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 Slackbot in your server logs
Search the web server access log for the token. The command below counts Slackbot requests per URL on Nginx or Apache.
grep -i "Slackbot" 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.
Slackbot user agent string
The full user agent Slack publishes for Slackbot. Version numbers such as Chrome/W.X.Y.Z change over time, so match the token, not the whole string.
Slackbot-LinkExpanding (+https://api.slack.com/robots)Slackbot FAQ
Slackbot identifies itself with the robots.txt token "Slackbot". A typical request header reads: Slackbot-LinkExpanding (+https://api.slack.com/robots)
Yes. Slack states that Slackbot follows robots.txt rules written for the "Slackbot" token.
Blocking a social preview bot has no effect on search rankings. No direct effect on AI answers, but shared links lose their title, image and description, which usually lowers clicks from social and chat apps.
Add two lines to the robots.txt file at the root of each domain and subdomain: "User-agent: Slackbot" followed by "Disallow: /". The token is case-insensitive. Changes can take up to 24 hours to be picked up.
Not reliably. Slack publishes no IP list or reverse DNS pattern for Slackbot, so anyone can send the same user agent. Rate-limit unusual volume instead of trusting the name.
Search your server access log for "Slackbot", for example with: grep -i "Slackbot" access.log. The AI Log File Analyzer by Justin Hà counts visits per AI bot from an uploaded log file.
Sources: Slack crawler documentation. 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.
