Safe Official docs Social Bots

Slack Link Expander

Q: What is the official user-agent string for Slack Link Expander?

The official user-agent string for Slack Link Expander is: Slackbot-LinkExpanding . Use this exact string in robots.txt, Nginx, Apache, or Cloudflare firewall rules to target this bot. Matching in robots.txt is case-insensitive. Verify a request genuinely comes from Slack Link Expander by performing a reverse-DNS lookup on the source IP.

Q: Is Slack Link Expander safe?

Yes, Slack Link Expander is a safe and legitimate crawler operated by Slack. It follows the Robots Exclusion Protocol (RFC 9309) and can be controlled with standard robots.txt rules.

Q: Will blocking Slack Link Expander hurt my SEO?

🔶 AI Visibility Trade-off - Blocking Slack Link Expander will not hurt Google or Bing rankings, but it can remove your content from AI search answers and assistant citations powered by this crawler. Block only if you have a deliberate reason.

Q: How do I block Slack Link Expander in robots.txt?

Add the following lines to your /robots.txt file: User-agent: Slackbot-LinkExpanding Disallow: / This instructs Slack Link Expander not to crawl any path on your site. To block only specific sections, replace / with the path (e.g., Disallow: /blog/ ).

Q: How do I verify if Slack Link Expander is crawling my site?

Search your web server access logs for the string Slackbot-LinkExpanding (case-insensitive: grep -i "Slackbot-LinkExpanding" /var/log/nginx/access.log ). Filter by user-agent in your log analytics tool (GoAccess, AWStats, etc.).

Operated by Slack

Scout's quick take

Slackbot-LinkExpanding (Slack Link Expander) fetches your page to build the preview card when someone shares a link. Blocking it leaves shared links without a title or image.

# Block only if you really mean to
User-agent: Slackbot-LinkExpanding
Disallow: /

Test my site for AI crawlers Build a full robots.txt

Quick Facts

User-Agent:: Slackbot-LinkExpanding
Category:: Social Bots
Operator:: Slack
Safety:: Safe
Blocking Impact:: Low - No SEO ranking impact
SEO Impact Score:: 2/10
Official docs:: api.slack.com

Confirmed by the operator

Slack names Slackbot-LinkExpanding on its own documentation page, linked above. The token, purpose and robots.txt behaviour on this profile come from that page, re-checked on October 19, 2026.

What is Slack Link Expander?

Slack Link Expander is an AI crawler operated by Slack. It uses the user-agent string Slackbot-LinkExpanding and follows the Robots Exclusion Protocol.

Slack Link Expander is an AI crawler operated by Slack. It uses the user-agent string Slackbot-LinkExpanding and follows the Robots Exclusion Protocol.
Slack Link Expander uses the user-agent token Slackbot-LinkExpanding. You can control it via robots.txt, meta tags (noai), or the emerging llms.txt standard. Robots.txt is voluntary; for hard enforcement, combine it with server-level IP blocking.

What happens if you block Slack Link Expander?

🔶 AI Visibility Trade-off - Blocking Slack Link Expander will not hurt Google or Bing rankings, but it can remove your content from AI search answers and assistant citations powered by this crawler. Block only if you have a deliberate reason.

Generally safe to allow; provides legitimate crawling value.

How to block Slack Link Expander with robots.txt

<code>User-agent: Slackbot-LinkExpanding</code> - Matching is case-insensitive. Robots.txt is fetched from the root of each subdomain separately.

Block completely (robots.txt)

User-agent: Slackbot-LinkExpanding
Disallow: /

Allow all (robots.txt)

User-agent: Slackbot-LinkExpanding
Allow: /

Block private only (robots.txt)

User-agent: Slackbot-LinkExpanding
Disallow: /private/
Disallow: /api/
Disallow: /admin/
Allow: /

Nginx server block

# Nginx: Hard-block Slack Link Expander
if ($http_user_agent ~* "Slackbot-LinkExpanding") {
    return 403 "Bot blocked";
}

Apache .htaccess

# Apache: Hard-block Slack Link Expander
SetEnvIfNoCase User-Agent "Slackbot-LinkExpanding" bad_bot
Order Allow,Deny
Allow from all
Deny from env=bad_bot

Meta robots tag

X-Robots-Tag header

X-Robots-Tag: noindex, nofollow

Is Slack Link Expander safe to allow?

Yes, Slack Link Expander is a safe and legitimate crawler operated by Slack. It follows the Robots Exclusion Protocol (RFC 9309) and can be controlled with standard robots.txt rules.

Verify by reverse-DNS lookup: legitimate Slack Link Expander requests resolve to Slack's domain.

What does Slack Link Expander do?

Understanding Slack Link Expander's purpose helps you decide whether to allow or block it.

Indexes web pages for AI-powered search answers
Surfaces your content as citations inside AI search results
Builds a knowledge index used to answer user questions
Allowing it can increase visibility in AI search
Respects robots.txt directives

Slack Link Expander in context

Slack Link Expander is a utility crawler operated by Slack. In plain terms, it fetches a page to build a link preview when someone shares it. Our database files it under social preview bots and ranks it Tier 5, low-priority crawlers with limited upside for most sites. 8 of the 9 social preview bots in our database share this tier.

Its safety rating is safe and its blocking impact is not documented. So the decision about Slack Link Expander rests on what you want from Slack, not on its behaviour. How we rate safety and impact.

How site owners treat Slack Link Expander

Our robots.txt study of the Tranco top 10,000 did not track Slackbot-LinkExpanding as a named token, so we do not publish an adoption figure for it. If you run a large site, your own logs are the best evidence of how often it visits.

Does it follow robots.txt?

Slack Link Expander's operator does not clearly document how it treats robots.txt. Write the Slack Link Expander rule anyway, then confirm in your logs that its requests stop.

Slack crawlers and close alternatives

Slack Link Expander is one of 2 Slack crawlers in our database. A User-agent: Slackbot-LinkExpanding group controls Slack Link Expander only; the other Slack tokens below need their own lines.

Slackbot-LinkExpanding: this crawler (Tier 5)
Slackbot: Slack Preview, fetches a page to build a link preview when someone shares it (Tier 5)

To give Slack Link Expander the same answer as its siblings, stack User-agent: Slackbot-LinkExpanding with their lines above one set of rules; to treat Slack Link Expander differently, give it its own group.

Other social preview bots that do the same job (fetches a page to build a link preview when someone shares it) include FacebookBot from Meta, facebookexternalhit from Meta, LinkedInBot from LinkedIn, Pinterestbot from Pinterest, Quora-Bot from Quora, Twitterbot from X (Twitter). Deciding about Slack Link Expander is usually a decision about the whole group, so check how your file treats these too.

We first recorded Slackbot-LinkExpanding on September 22, 2026. Slack documents it on api.slack.com, and we recheck that page before each release.

Which rule Slack Link Expander actually follows

Slack Link Expander reads exactly one group in robots.txt, the most specific one that names Slackbot-LinkExpanding, and never combines rules across groups. This short file shows the trap:

User-agent: *
Disallow: /private/

User-agent: Slackbot-LinkExpanding
Disallow: /drafts/

Find the group. Slack Link Expander looks for a group naming Slackbot-LinkExpanding. One exists, so it ignores User-agent: * completely.
Apply only that group. It is refused /drafts/ and nothing else.
The surprise. /private/ is open to Slack Link Expander, because that rule lives in the * group it no longer reads. To keep it out of both, repeat Disallow: /private/ inside its own group.

Test yourself: does a rule under User-agent: * apply to Slack Link Expander if the file also has a User-agent: Slackbot-LinkExpanding group?

No. Once a group names it, Slack Link Expander reads only that group. Put every rule you want it to follow inside its own group.

Test yourself: will blocking Slack Link Expander remove your pages from AI answers?

Often, yes. Slack Link Expander is a utility crawler, so pages it cannot fetch can drop out of the answers or results it supports.

Test yourself: is User-agent: slackbot-linkexpanding the same as User-agent: Slackbot-LinkExpanding?

Yes. RFC 9309 makes user-agent matching case-insensitive. Paths are a different story: Disallow: /Blog/ does not block /blog/.

Should you allow Slack Link Expander? Decide by situation

Recommended setting for Slack Link Expander by type of site
If you are...	Recommended setting
You publish content and want AI answers to cite it	Low stakes either way. It does not decide whether AI answers cite you.
You license content and want to stop AI training	Blocking it does not stop training, because Slack Link Expander is a utility crawler. Block the operator's training crawler instead.
You run an online shop	Allow it unless your logs show it is costly.
Your server is under load from bots	Rate-limit before blocking. It is rated safe in our database.

Check Slack Link Expander on your own site

Open /robots.txt on your domain and search for Slackbot-LinkExpanding. If it is not named, it follows User-agent: *.
List the Disallow lines in the group Slack Link Expander follows and test your key URLs against them; the longest match wins, and Allow wins a tie.
Look beyond the file. A firewall or bot manager can refuse Slack Link Expander even when robots.txt allows it, and that never shows in the file.
Run our AI bot crawlability test to see how Slack Link Expander and every other crawler we track are treated in one pass, including firewall refusals.

Common mistakes with Slack Link Expander

The errors we see most often with Slack Link Expander in the files and firewalls we test:

Treating Slack Link Expander as an AI or search crawler. Blocking it has little effect on visibility; decide based on load and what it does with your data.
Relying on robots.txt alone when Slack Link Expander is rated caution or aggressive. Back the rule with a server-side block.
Blocking Slack Link Expander by IP alone. Ranges change; match the token and verify with logs.

All three hide inside a file that looks correct, so check Slack Link Expander from outside after every change.

Spotting Slack Link Expander in your logs

robots.txt says what Slack Link Expander may do; your access logs show what it actually did.

Count requests

On a server with standard Nginx or Apache logs, this counts matching requests per day (adjust the log path for your host):

grep -iE "Slackbot-LinkExpanding" /var/log/nginx/access.log \
  | awk '{print $4}' | cut -d: -f1 | sort | uniq -c

And this shows which paths it requested most, which is the quickest way to see whether your Disallow lines are being respected:

grep -iE "Slackbot-LinkExpanding" /var/log/nginx/access.log \
  | awk '{print $7}' | sort | uniq -c | sort -rn | head -20

Check the requests are genuine

Anyone can send the Slack Link Expander user-agent, so confirm the source before acting on a match:

Slackbot-LinkExpanding: we hold no published IP list, so use reverse DNS where the operator documents a hostname and treat an unverifiable Slack Link Expander request with caution.

Frequently Asked Questions

What is the official user-agent string for Slack Link Expander?

The official user-agent string for Slack Link Expander is: Slackbot-LinkExpanding. Use this exact string in robots.txt, Nginx, Apache, or Cloudflare firewall rules to target this bot. Matching in robots.txt is case-insensitive. Verify a request genuinely comes from Slack Link Expander by performing a reverse-DNS lookup on the source IP.

Is Slack Link Expander safe?

Yes, Slack Link Expander is a safe and legitimate crawler operated by Slack. It follows the Robots Exclusion Protocol (RFC 9309) and can be controlled with standard robots.txt rules.

Will blocking Slack Link Expander hurt my SEO?

How do I block Slack Link Expander in robots.txt?

Add the following lines to your /robots.txt file:

User-agent: Slackbot-LinkExpanding
Disallow: /

This instructs Slack Link Expander not to crawl any path on your site. To block only specific sections, replace / with the path (e.g., Disallow: /blog/).

Does Slack Link Expander respect robots.txt?

Slack Link Expander is operated by Slack and is expected to fetch and parse /robots.txt before crawling, following RFC 9309. For hard enforcement, combine robots.txt with server-level IP or user-agent blocking.

How do I verify if Slack Link Expander is crawling my site?

Search your web server access logs for the string Slackbot-LinkExpanding (case-insensitive: grep -i "Slackbot-LinkExpanding" /var/log/nginx/access.log). Filter by user-agent in your log analytics tool (GoAccess, AWStats, etc.).