What Slack-ImgProxy does
Slack-ImgProxy is the Slack service that fetches and caches images posted in Slack channels. Slack proxies these images to hide referrer information from the origin server, ensure the images are delivered over HTTPS, and improve performance. It identifies itself with a user-agent such as Slack-ImgProxy 0.19 with a link to api.slack.com/robots.
How to control Slack-ImgProxy
Target Slack-ImgProxy in your robots.txt with the Slack-ImgProxy token. Rules apply per bot, so you can allow this one while blocking others, or the reverse.
Allow Slack-ImgProxy
User-agent: Slack-ImgProxy
Allow: /Block Slack-ImgProxy
User-agent: Slack-ImgProxy
Disallow: /Slack states it does not currently honor robots.txt files, on the grounds that its requests are made on behalf of users rather than by a crawler.
How to identify Slack-ImgProxy
Temso identifies Slack-ImgProxytraffic by matching the request's User-Agent header against this pattern. User-agent strings can be spoofed, so treat a match as an indication, not proof.
Slack-ImgProxySlack-ImgProxy FAQ
What is Slack-ImgProxy?
Slack-ImgProxy is Slack's image proxy, which fetches and caches images that users post in Slack channels. Slack proxies the images to hide referrer information, ensure HTTPS delivery, and improve performance.
How do I block Slack-ImgProxy?
Adding a "User-agent: Slack-ImgProxy" group to robots.txt will not stop it, because Slack states it does not currently honor robots.txt files, since requests are made on behalf of users. To have your site blocklisted, Slack directs owners to contact its help system or @slackapi on Twitter.
About Operational Bots
Monitoring, security scanning, link previews, webhooks, and feed fetchers: the utility traffic that keeps integrations and shared links working.
Most of this traffic is service-critical or user-triggered. Webhooks and previews don't follow robots.txt, and blocking them tends to break things you rely on.
