Slack-ImgProxy

social-preview Slack-ImgProxy

Slack's image proxy web crawler bot

About this crawler

Slack-ImgProxy is a web crawler identified by the regular-expression pattern Slack-ImgProxy in the User-Agent request header. It is categorised as social-preview. Use the regex above to detect, log, allow, or block Slack-ImgProxy traffic in your web server, CDN edge rules, or robots.txt.

Block-rate · top 25k sites

0.065%
latest snapshot
2026-06-04
matched key: Slack-ImgProxy
2026-05-012026-06-040.11%

Technical details

Name
Slack-ImgProxy
Pattern
Slack-ImgProxy
Tags
social-preview
Reference
https://api.slack.com/robots
Added
2016/04/25
rDNS suffixes
.slack-edge.com, .slack.com
Instances
6 known sample(s)

rDNS verification (FCrDNS)

Verify a request is genuinely Slack-ImgProxy with forward-confirmed reverse DNS: the client IP's PTR record must end in one of the suffixes below and a forward A/AAAA lookup of that hostname must return the same IP. UA strings alone are spoofable; FCrDNS is not.

Sample User-Agent strings

Slack-ImgProxy (+https://api.slack.com/robots)
Slack-ImgProxy 0.59 (+https://api.slack.com/robots)
Slack-ImgProxy 0.66 (+https://api.slack.com/robots)
Slack-ImgProxy 1.106 (+https://api.slack.com/robots)
Slack-ImgProxy 1.138 (+https://api.slack.com/robots)
Slack-ImgProxy 149 (+https://api.slack.com/robots)

Block this crawler

robots.txt — disallow Slack-ImgProxy:

User-agent: Slack-ImgProxy Disallow: /

Apache .htaccess — return 403:

RewriteEngine On RewriteCond %{HTTP_USER_AGENT} Slack-ImgProxy [NC] RewriteRule .* - [F,L]

Nginx — return 403 inside a server block:

if ($http_user_agent ~* "Slack-ImgProxy") { return 403; }
← back to all crawlers