Caution Official docs SEO Tools

SemrushBot-OCOB

Operated by Semrush

Quick Facts

User-Agent:
SemrushBot-OCOB
Category:
SEO Tools
Operator:
Semrush
Safety:
Caution
Blocking Impact:
Varies - Evaluate before blocking
SEO Impact Score:
0/10
Official docs:
www.semrush.com

Confirmed by the operator

Semrush names SemrushBot-OCOB 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 SemrushBot-OCOB?

SemrushBot-OCOB is the Semrush token used for Content Toolkit reports, per Semrush's bot page.

It identifies itself with the token SemrushBot-OCOB. Semrush documents it at semrush.com.

What happens if you block SemrushBot-OCOB?

No effect on Google or Bing. It only stops Semrush Content Toolkit fetching your pages; the backlink crawler (SemrushBot) and Site Audit (SiteAuditBot) need their own rules.
Consider blocking based on your content strategy.

How to block SemrushBot-OCOB with robots.txt

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

Block completely (robots.txt)
User-agent: SemrushBot-OCOB Disallow: /
Allow all (robots.txt)
User-agent: SemrushBot-OCOB Allow: /
Block private only (robots.txt)
User-agent: SemrushBot-OCOB Disallow: /private/ Disallow: /api/ Disallow: /admin/ Allow: /
Nginx server block
# Nginx: Hard-block SemrushBot-OCOB if ($http_user_agent ~* "SemrushBot\-OCOB") { return 403 "Bot blocked"; }
Apache .htaccess
# Apache: Hard-block SemrushBot-OCOB SetEnvIfNoCase User-Agent "SemrushBot\-OCOB" bad_bot Order Allow,Deny Allow from all Deny from env=bad_bot
Meta robots tag
<meta name="robots" content="noindex, nofollow">
X-Robots-Tag header
X-Robots-Tag: noindex, nofollow

Is SemrushBot-OCOB safe to allow?

SemrushBot-OCOB is rated Caution. Semrush documents it, so it is not a spoofing risk in itself, but it fetches content for uses you may not want to support. Decide on its purpose.

What does SemrushBot-OCOB do?

From Semrush's own documentation.

  • SemrushBot-OCOB is the Semrush token used for Content Toolkit reports, per Semrush's bot page.
  • No effect on Google or Bing. It only stops Semrush Content Toolkit fetching your pages; the backlink crawler (SemrushBot) and Site Audit (SiteAuditBot) need their own rules.

SemrushBot-OCOB in context

SemrushBot-OCOB is a utility crawler operated by Semrush. In plain terms, it checks pages for an SEO, uptime or analytics service. Our database files it under SEO tools and ranks it Tier 4, specialist crawlers that matter to particular sites or markets. 19 of the 19 SEO tools in our database share this tier.

Its safety rating is caution and its blocking impact is not documented. So the decision about SemrushBot-OCOB rests on what you want from Semrush, not on its behaviour. How we rate safety and impact.

How site owners treat SemrushBot-OCOB

Our robots.txt study of the Tranco top 10,000 did not track SemrushBot-OCOB 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?

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

Semrush crawlers and close alternatives

SemrushBot-OCOB is one of 3 Semrush crawlers in our database. A User-agent: SemrushBot-OCOB group controls SemrushBot-OCOB only; the other Semrush tokens below need their own lines.

  • SemrushBot-OCOB: this crawler (Tier 4)
  • SemrushBot: Semrush SEO, checks pages for an SEO, uptime or analytics service (Tier 4)
  • SemrushBot-SWA: Semrush Writing Assistant, checks pages for an SEO, uptime or analytics service (Tier 4)

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

Other SEO tools that do the same job (checks pages for an SEO, uptime or analytics service) include AhrefsBot from Ahrefs, AhrefsSiteAudit from Ahrefs, AwarioBot from Awario, AwarioRssBot from Awario, AwarioSmartBot from Awario, Chrome-Lighthouse from Google. Deciding about SemrushBot-OCOB is usually a decision about the whole group, so check how your file treats these too.

We first recorded SemrushBot-OCOB on March 17, 2026. Semrush documents it on semrush.com, and we recheck that page before each release.

Which rule SemrushBot-OCOB actually follows

SemrushBot-OCOB reads exactly one group in robots.txt, the most specific one that names SemrushBot-OCOB, and never combines rules across groups. This short file shows the trap:

User-agent: *
Disallow: /private/

User-agent: SemrushBot-OCOB
Disallow: /drafts/
  1. Find the group. SemrushBot-OCOB looks for a group naming SemrushBot-OCOB. One exists, so it ignores User-agent: * completely.
  2. Apply only that group. It is refused /drafts/ and nothing else.
  3. The surprise. /private/ is open to SemrushBot-OCOB, 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 SemrushBot-OCOB if the file also has a User-agent: SemrushBot-OCOB group?

No. Once a group names it, SemrushBot-OCOB reads only that group. Put every rule you want it to follow inside its own group.

Test yourself: will blocking SemrushBot-OCOB remove your pages from AI answers?

Often, yes. SemrushBot-OCOB is a utility crawler, so pages it cannot fetch can drop out of the answers or results it supports.

Test yourself: is User-agent: semrushbot-ocob the same as User-agent: SemrushBot-OCOB?

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

Related: how AI engines choose their sources

Should you allow SemrushBot-OCOB? Decide by situation

Recommended setting for SemrushBot-OCOB by type of site
If you are...Recommended setting
You publish content and want AI answers to cite itLow stakes either way. It does not decide whether AI answers cite you.
You license content and want to stop AI trainingBlocking it does not stop training, because SemrushBot-OCOB is a utility crawler. Block the operator's training crawler instead.
You run an online shopAllow it unless your logs show it is costly.
Your server is under load from botsRate-limit before blocking. It is rated caution in our database.

Check SemrushBot-OCOB on your own site

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

Common mistakes with SemrushBot-OCOB

The errors we see most often with SemrushBot-OCOB in the files and firewalls we test:

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

All three hide inside a file that looks correct, so check SemrushBot-OCOB from outside after every change.

Spotting SemrushBot-OCOB in your logs

robots.txt says what SemrushBot-OCOB 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 "SemrushBot-OCOB" /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 "SemrushBot-OCOB" /var/log/nginx/access.log \
  | awk '{print $7}' | sort | uniq -c | sort -rn | head -20

Check the requests are genuine

Anyone can send the SemrushBot-OCOB user-agent, so confirm the source before acting on a match:

  • SemrushBot-OCOB: we hold no published IP list, so use reverse DNS where the operator documents a hostname and treat an unverifiable SemrushBot-OCOB request with caution.

Frequently Asked Questions

What is the official user-agent string for SemrushBot-OCOB?
The official user-agent string for SemrushBot-OCOB is: SemrushBot-OCOB. This is the exact string you must use in robots.txt, Nginx, Apache, or Cloudflare firewall rules to target this bot. User-agent matching in robots.txt is case-insensitive, but the string must be spelled correctly. You can verify that a request genuinely comes from SemrushBot-OCOB by performing a reverse-DNS lookup on the source IP - legitimate bots resolve back to their operator's domain.
Is SemrushBot-OCOB safe?
SemrushBot-OCOB is rated Caution. Semrush documents it, so it is not a spoofing risk in itself, but it fetches content for uses you may not want to support. Decide on its purpose.
Will blocking SemrushBot-OCOB hurt my SEO?
No effect on Google or Bing. It only stops Semrush Content Toolkit fetching your pages; the backlink crawler (SemrushBot) and Site Audit (SiteAuditBot) need their own rules.
How do I block SemrushBot-OCOB in robots.txt?
Add the following lines to your /robots.txt file:
User-agent: SemrushBot-OCOB
Disallow: /

This instructs SemrushBot-OCOB not to crawl any path on your site. The Disallow: / directive covers the entire domain including subfolders. To only block specific sections, replace / with the path (e.g., Disallow: /blog/). Note: robots.txt is publicly readable - any bot or human can inspect it at yourdomain.com/robots.txt.
Does SemrushBot-OCOB respect robots.txt?
Yes. Semrush documents a separate robots.txt group for it: User-agent: SemrushBot-OCOB.
How do I verify if SemrushBot-OCOB is crawling my site?
Search your web server access logs for the string SemrushBot-OCOB (case-insensitive grep: grep -i "SemrushBot-OCOB" /var/log/nginx/access.log). You can also check Google Search Console → Coverage → Crawl Stats for Googlebot variants. For SemrushBot-OCOB specifically, filter by user-agent in your log analysis tool (GoAccess, AWStats, etc.).
What is the crawl frequency of SemrushBot-OCOB?
Crawl frequency data for SemrushBot-OCOB is not publicly documented. Monitor your logs to understand actual visit patterns.
Can I block SemrushBot-OCOB from specific pages only?
Yes. Instead of a global Disallow: / you can restrict SemrushBot-OCOB to specific paths:
User-agent: SemrushBot-OCOB
Disallow: /private/
Disallow: /staging/
Allow: /

This allows SemrushBot-OCOB everywhere except the listed paths. Path matching in robots.txt uses prefix matching - Disallow: /private/ blocks /private/page.html but NOT /public/private/.
Why would I want to block SemrushBot-OCOB?
There are two main reasons to block SemrushBot-OCOB:
1. Competitive intelligence: Semrush users (your competitors) can analyse your backlink profile, keyword rankings, and site structure. Blocking prevents this.
2. Crawl budget: If your site is large, SEO tool crawlers consume crawl bandwidth without contributing to search rankings. Blocking frees up server resources for search engine bots.
The trade-off: you also become invisible in Semrush's backlink database, meaning links pointing TO your site from other domains won't appear in competitor reports either.

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