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What is Slackbot-LinkExpanding?

Slackbot-LinkExpanding is the robot Slack sends when a user posts a link into a channel. Slack says it fetches as little of the page as it can, using HTTP Range headers, to read oEmbed, Twitter Card and Open Graph tags. Slack caches the response for around 30 minutes.

Operator
Slack
Purpose
Fetches a page's meta tags when someone posts its link in Slack.
robots.txt token
Slackbot-LinkExpanding
Example user agent
Slackbot-LinkExpanding 1.0 (+https://api.slack.com/robots)
How to verify
Slack publishes no IP list or reverse DNS domain for its robots.
Operator documentation
https://api.slack.com/robots
Last verified

How often is Slackbot-LinkExpanding impersonated?

We have not measured requests claiming to be Slackbot-LinkExpanding yet, so we show no share.

This directory measures requests between 3 July 2026 and 28 September 2026. The fake crawler report covers its own, earlier window (late June to 21 September 2026), so its figures differ from the ones here. Read it for the method.

Have a request that claims to be Slackbot-LinkExpanding? Check its IP address.

Should you block Slackbot-LinkExpanding?

Allow it if
people share your pages in Slack.
Block it if
you do not want preview cards in Slack. Ask Slack to add your site to its blocklist, because a robots.txt rule has no effect.
What blocking changes
A robots.txt rule does not stop it. Slack says to contact it if you want your site blocked from Slack embeds.

To block it, add this group to your robots.txt. Slack says it does not currently honor robots.txt files, because the robot does not follow links and acts on behalf of a person.

User-agent: Slackbot-LinkExpanding
Disallow: /

robots.txt only asks. It does nothing against a client that ignores it or only pretends to be Slackbot-LinkExpanding. Stopping those takes verification at your edge.

Related bots

  • Discordbot (Discord): Visits a link shared in a Discord message to build its preview.
  • facebookexternalhit (Meta): Builds link previews when content is shared on Meta's apps.
  • Pinterestbot (Pinterest): Indexes pages behind Pins and keeps Pin details up to date.
  • Twitterbot (X): Fetches card markup when a link is shared on X.

See which bots reach your site, and which of them are who they claim to be.

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