What is SemrushBot? Semrush's SEO crawler
SemrushBot is Semrush's web crawler. Semrush says the data it collects feeds tools including Backlink Analytics, Site Audit, Backlink Audit and Topic Research.
93 of the 1664 major websites we measure block SemrushBot in robots.txt (6%). 97 of those sites name it directly in their robots.txt; the rest are covered by a wildcard rule.
Key facts
| Fact | Detail |
|---|---|
| Operator | Semrush |
| Used for | Semrush's backlink, site audit and content tools |
| Type | SEO tool. Collects web data for an SEO tool. Listed here because people look it up beside AI crawlers. It isn't counted in the AI crawler figures. |
| robots.txt token | SemrushBot |
| Operator's documentation | Read it here |
What blocking SemrushBot does
Semrush recommends robots.txt as the main way to block it, with a separate file for each subdomain, and says some of its tools use their own bots that can be blocked separately. It says changes can take up to an hour to apply.
How to allow or block SemrushBot
Add one of these groups to the robots.txt file at the root of your domain. It is a stated preference that well-behaved crawlers read, not an enforcement mechanism.
User-agent: SemrushBot Disallow: /
User-agent: SemrushBot Allow: /
SemrushBot user agent string
Semrush's page doesn't list a full string, so look for SemrushBot in the user agent field of your logs.
How to verify a request is really SemrushBot
Anyone can put a crawler's name in a user agent string, so the name alone proves nothing. We did not find a published IP list or reverse DNS rule from Semrush.
How to whitelist SemrushBot in a firewall or CDN
robots.txt only states a preference. A firewall, CDN or bot protection service can still refuse the request, and the crawler then gets an error even though robots.txt allows it.
- Check that no group in your robots.txt blocks it, using the rule above.
- Add an allow rule in your firewall or CDN that matches the name in the user agent. Keep the rule narrow, because anyone can copy a name.
- Check your server logs for a 200 response from SemrushBot afterwards.
On Cloudflare, also check AI Crawler and Agent access policies, which can block search, agent and training traffic across a site.
Why SemrushBot gets a 403 or 405 error
A 403 means the server refused the request, which usually points to a firewall or bot rule. A 405 means the server refused the request's method, so check any rule that only permits certain methods. A crawler that obeys robots.txt won't request a page it is told to avoid, so an error in your logs points to your server's configuration. To stop it deliberately at the server, this nginx rule returns a 403:
if ($http_user_agent ~* "SemrushBot") {
return 403;
}Who blocks SemrushBot, by sector
| Sector | Sites measured | Blocking | Share |
|---|---|---|---|
| News publishers | 182 | 23 | 13% |
| Social and media platforms | 115 | 12 | 10% |
| Reference and research | 114 | 10 | 9% |
| Technology media | 126 | 11 | 9% |
| AI companies | 128 | 9 | 7% |
| Government and institutions | 98 | 7 | 7% |
| Travel | 86 | 4 | 5% |
| Developer references | 160 | 6 | 4% |
| E-commerce and retail | 92 | 3 | 3% |
| Finance and business media | 94 | 2 | 2% |
| Health publishers | 89 | 2 | 2% |
| SaaS platforms | 196 | 3 | 2% |
| SEO and marketing tools | 86 | 1 | 1% |
| Hosting and infrastructure | 98 | 0 | 0% |
Sites blocking SemrushBot
academia.edu, afterpay.com, aliexpress.com, alignmentforum.org, allafrica.com, arm.com, arxiv.org, azcentral.com, bandcamp.com, bild.de, biorxiv.org, breakingnews.ie, bundesregierung.de, caltech.edu, cmake.org, computerbase.de, consilium.europa.eu, csail.mit.edu, css-tricks.com, devclass.com, distill.pub, eluniversal.com.mx, etymonline.com, expedia.com, facebook.com, flickr.com, france24.com, getapp.com, gnu.org, golem.de, hackernoon.com, hrw.org, illinois.gov, imdb.com, influxdata.com, instacart.com, instagram.com, krebsonsecurity.com, lastampa.it, lefigaro.fr, lemonde.fr, leparisien.fr, lesechos.fr, lesswrong.com, librarything.com, linguee.com, lobste.rs, magento.com, meta.ai, metacritic.com, musicbrainz.org, nejm.org, netflix.com, news24.com, nidirect.gov.uk, notion.so, orbitz.com, poe.com, psychologytoday.com, publico.pt, and 33 more in the full dataset.
Sites that allow SemrushBot by name
apollo.io, barrons.com, boingboing.net, bupa.co.uk, digitaltrends.com, disneyplus.com, eff.org, fortinet.com, freebsd.org, g2.com, intel.com, lightspeedhq.com, marketwatch.com, mongodb.com, msnbc.com, newegg.com, news.com.au, newstatesman.com, pinterest.com, producthunt.com, sitepoint.com, slate.com, thesun.co.uk, thetimes.co.uk, washingtonpost.com, wikidata.org, wikipedia.org, wikiquote.org, wikisource.org, wikivoyage.org, wiktionary.org, wsj.com.
Other Semrush crawlers
SiteAuditBot (SEO site audit), SemrushBot-BA (SEO backlink audit), SemrushBot-SI (SEO page checks), SemrushBot-SWA (SEO writing checks), SplitSignalBot (SEO A/B tests), SemrushBot-OCOB (SEO content tools), SemrushBot-FT (plagiarism checks), RyteBot (SEO site audit), SemrushBot-ESI (enterprise site data).
See all 36 AI crawlers, the rule change log or the full study. Being reachable is only the first step: how AI search engines choose what to cite covers the rest.
Cite this data
You are welcome to quote or republish these figures. Please credit IndexHalo with a link to this page (CC BY 4.0). All our datasets are on the data page.
IndexHalo. "SemrushBot block rate across major websites." Measured 12 November 2026. https://www.indexhalo.com/ai-crawlers/semrushbot/
<a href="https://www.indexhalo.com/ai-crawlers/semrushbot/">SemrushBot block rate across major websites, IndexHalo</a>