SemrushBot-OCOB
Semrush operates SemrushBot-OCOB, an SEO-tool crawler that Semrush says crawls sites for its Content Toolkit reports. It obeys robots.txt under the SemrushBot-OCOB User-agent token, which is the only place Semrush documents it. Semrush publishes no IP ranges and no reverse DNS suffix, stating it does not use consecutive IP blocks, so no verification method is documented.
What SemrushBot-OCOB does
Semrush does not publish a full user agent string for this crawler, so the only documented identifier is the user agent token SemrushBot-OCOB. The operator's own wording is brief and ties the bot to one product, the Content Toolkit and its reports. Semrush gives no further description of what the visits collect or how often they occur, so anything beyond the token and the product name is undocumented.
Because this is an SEO-tool crawler rather than a search engine, allowing or blocking it has no documented effect on where your site appears in search results. Blocking it removes your site's data from the Content Toolkit reports; allowing it lets those reports include your pages. Semrush documents the bot on its /bot/ page only as a robots.txt User-agent line paired with Disallow: /, which is the exact rule to add if you want it to stop crawling.
Verification is the weak point. Semrush states that it does not use any consecutive IP blocks, and it publishes neither an IP list nor a reverse DNS suffix, so there is no operator-backed way to confirm that a request claiming to be SemrushBot-OCOB came from Semrush. Site owners have the user agent token alone. JavaScript execution is also undocumented; Semrush does not say whether the crawler renders pages.
Operator note. Semrush documents this token only as a robots.txt User-agent that can be blocked with "Disallow: /" on its bot page. JavaScript execution and IP addresses are not documented.
Controlling SemrushBot-OCOB with robots.txt
Use the token SemrushBot-OCOB in robots.txt. Semrush documents that SemrushBot-OCOB honors robots.txt directives.
User-agent: SemrushBot-OCOB
Disallow: /User-agent: SemrushBot-OCOB
Allow: /Verifying a request is really SemrushBot-OCOB
Anyone can put SemrushBot-OCOB in a User-Agent header. The operator does not document a verification method. Semrush states that "we do not use any consecutive IP blocks".
Common questions
Should I block SemrushBot-OCOB?
Block it if you do not want your site included in Semrush Content Toolkit reports; it is an SEO-tool crawler, and blocking it has no documented effect on search rankings. Add User-agent: SemrushBot-OCOB followed by Disallow: / to robots.txt, which is the rule Semrush itself documents.
How do I verify SemrushBot-OCOB?
The operator's documentation gives no method. Semrush says it does not use any consecutive IP blocks, publishes no IP list and documents no reverse DNS hostname. The only identifier is the SemrushBot-OCOB token in the user agent header, which on its own does not prove the request came from Semrush.
Does SemrushBot-OCOB run JavaScript?
The operator's documentation does not say. Semrush's bot page lists SemrushBot-OCOB only as a robots.txt User-agent token with a Disallow example and gives no detail on rendering or script execution. Treat JavaScript execution as undocumented.
Sources
Every fact on this page was checked against Semrush's own documentation, listed below, and re-checked by a second reviewer before publication. Reviewed September 2026.
Related crawlers
This registry documents how operators describe their own bots so site owners can identify and control them. It does not publish third-party IP lists or guess at undocumented behaviour. To see how your own site responds to automated visitors, the bot detection scanner reads a URL's live response and names the protection it finds.