What is SemrushBot-OCOB?

SemrushBot-OCOB is a bot in the AI crawlers category, operated by Semrush.

Bot name
SemrushBot-OCOB
Operator
Semrush
Category
AI Crawlers
Type
Bot
Respects robots.txt
Yes
robots.txt user agent
SemrushBot-OCOB
Signs requests (Web Bot Auth)
No

About SemrushBot-OCOB

Semrush is an all-in-one tool suite for improving online visibility and discovering marketing insights.

AI crawlers collect web pages in bulk to build training data for large language models and other AI systems. They take content without sending visitors back. Most publishers block them in robots.txt or at the WAF unless they have a licensing deal with the operator.

SemrushBot-OCOB user agent

SemrushBot-OCOB identifies itself with this user agent string:

  • Mozilla/5.0 (compatible; SemrushBot-OCOB/1; +https://www.semrush.com/bot/)

Anyone can copy a user agent string. Transfon Security also checks where each request comes from, so a request that claims to be a known crawler but comes from the wrong network is treated as a fake, not as the real crawler.

How to block SemrushBot-OCOB in robots.txt

SemrushBot-OCOB follows robots.txt, so these rules stop it crawling the paths you choose. robots.txt is a plain text file at the root of your domain, such as https://example.com/robots.txt.

Block SemrushBot-OCOB from the whole site

User-agent: SemrushBot-OCOB
Disallow: /

Block SemrushBot-OCOB from some folders

User-agent: SemrushBot-OCOB
Disallow: /private/
Disallow: /search

Allow SemrushBot-OCOB only on some folders

User-agent: SemrushBot-OCOB
Allow: /blog/
Disallow: /

Allow SemrushBot-OCOB and block other crawlers

User-agent: SemrushBot-OCOB
Allow: /

User-agent: *
Disallow: /

Things to know

  • Each host needs its own file. Rules on www.example.com do not apply to shop.example.com.
  • A crawler obeys only the most specific group that names it. Once you add a User-agent: SemrushBot-OCOB group, SemrushBot-OCOB ignores your User-agent: * rules, so repeat any that should still apply.
  • The user agent name is not case sensitive. We take SemrushBot-OCOB from SemrushBot-OCOB's user agent; check Semrush's own documentation if it publishes a different robots.txt name.
  • Crawlers cache robots.txt, so changes can take up to a day to apply. Disallow stops crawling but does not remove pages already collected or indexed.

Limits of robots.txt

  1. SemrushBot-OCOB may not follow the rule. SemrushBot-OCOB says it follows robots.txt, but nothing enforces that. Changes can take a day to apply, the operator can change its policy, and other crawlers from Semrush use different names and rules.
  2. The user agent could be fake. robots.txt matches the name a request claims. Anyone can send SemrushBot-OCOB's user agent, and a scraper using it is not bound by Semrush's robots.txt policy. Only checking the source network tells a real SemrushBot-OCOB from a fake one.

Treat robots.txt as a statement of your policy, and enforce it where requests arrive.

Who should care about SemrushBot-OCOB

Publishers

SemrushBot-OCOB takes articles for AI training without sending readers back, and its page loads count as invalid traffic if your ad tags fire. Decide whether to license, limit or block it, and keep it out of ad requests.

Transfon Security for publishers

Media buyers and advertisers

Visits from SemrushBot-OCOB to your landing pages are not people. Keep them out of conversion, retargeting and audience data so you do not pay to reach a crawler.

Transfon Security for advertisers

E-commerce

SemrushBot-OCOB can copy product descriptions, prices and reviews in bulk. Allow it on pages you want AI models to know about and block it on search, cart and account pages.

Transfon Security for e-commerce

SaaS and APIs

SemrushBot-OCOB can fetch documentation and public app pages at scale. Rate limit it so it does not slow the product for paying users.

Transfon Security for SaaS and APIs

Block SemrushBot-OCOB with Transfon Security

robots.txt is a request, not an enforcement. Transfon Security shows SemrushBot-OCOB by name in the Top Bots report, so you can see how often it visits and which pages it reads. Block or allow it with a User Agent rule, or slow it down with a rate limit decision rule.

Transfon Security

Control SemrushBot-OCOB on your site

  • See every SemrushBot-OCOB visit and the pages it reads
  • Spot bots that fake trusted crawler names
  • Block, allow or rate limit SemrushBot-OCOB with one rule
  • Works with or without robots.txt support

Frequently asked questions

What is SemrushBot-OCOB?

SemrushBot-OCOB is a bot in the AI crawlers category, operated by Semrush. Semrush is an all-in-one tool suite for improving online visibility and discovering marketing insights.

Does SemrushBot-OCOB respect robots.txt?

Yes. SemrushBot-OCOB follows robots.txt, so a Disallow rule for the SemrushBot-OCOB user agent stops it from crawling the paths you list.

How do I block SemrushBot-OCOB?

Add "User-agent: SemrushBot-OCOB" followed by "Disallow: /" to the robots.txt file at the root of your site. To enforce it, block requests whose user agent contains "SemrushBot-OCOB" at your WAF. In Transfon Security that is one User Agent block rule.

Is robots.txt enough to block SemrushBot-OCOB?

No. robots.txt is voluntary, so SemrushBot-OCOB may not follow it, and anyone can send SemrushBot-OCOB's user agent, so a fake SemrushBot-OCOB ignores your rule. Enforce the rule where requests arrive, at your WAF, and check the source network.

Should I block SemrushBot-OCOB?

AI crawlers collect web pages in bulk to build training data for large language models and other AI systems. They take content without sending visitors back. Most publishers block them in robots.txt or at the WAF unless they have a licensing deal with the operator.

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