SemrushBot: User Agent, robots.txt Rules & Safety Rating

Q: What is the official user-agent string for SemrushBot?

The official user-agent string for SemrushBot is: SemrushBot. 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 by performing a reverse-DNS lookup on the source IP - legitimate bots resolve back to their operator's domain.

Q: How do I block SemrushBot in robots.txt?

Add the following lines to your /robots.txt file: User-agent: SemrushBot Disallow: / This instructs SemrushBot 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.

Q: How do I verify if SemrushBot is crawling my site?

Search your web server access logs for the string SemrushBot (case-insensitive grep: grep -i "SemrushBot" /var/log/nginx/access.log). You can also check Google Search Console → Coverage → Crawl Stats for Googlebot variants. For SemrushBot specifically, filter by user-agent in your log analysis tool (GoAccess, AWStats, etc.).

Quick Facts

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

What is SemrushBot?

SemrushBot is the main crawler for Semrush, an all-in-one marketing toolkit. It collects data for SEO analysis and site audits.

SemrushBot is the main crawler for Semrush, an all-in-one marketing toolkit. It collects data for SEO analysis and site audits. SemrushBot is a commercial SEO analytics crawler operated by Semrush. It builds backlink graphs, crawls for technical SEO issues, and tracks keyword rankings. The user-agent SemrushBot is well-known and respected in the SEO industry. Blocking it removes your domain from Semrush's index, preventing competitors from analysing your backlink profile via their platform. However, other Semrush users also lose visibility into links pointing TO your site - weigh this trade-off carefully.

What happens if you block SemrushBot?

❓ **Impact Unknown** - The SEO consequences of blocking SemrushBot are not fully documented. Before blocking, check your analytics to confirm whether this bot generates referral traffic, review your server logs for crawl frequency, and test in a staging environment if possible.

Generally safe to allow; provides legitimate crawling value.

How to block SemrushBot with robots.txt

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

Block completely (robots.txt)

User-agent: SemrushBot
Disallow: /

Allow all (robots.txt)

User-agent: SemrushBot
Allow: /

Block private only (robots.txt)

User-agent: SemrushBot
Disallow: /private/
Disallow: /api/
Disallow: /admin/
Allow: /

Nginx server block

# Nginx: Hard-block SemrushBot
if ($http_user_agent ~* "SemrushBot") {
    return 403 "Bot blocked";
}

Apache .htaccess

# Apache: Hard-block SemrushBot
SetEnvIfNoCase User-Agent "SemrushBot" 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 SemrushBot safe to allow?

Yes, SemrushBot is a **safe and legitimate** crawler. It is operated by Semrush, which publicly documents its crawler at an official URL and follows the Robots Exclusion Protocol (RFC 9309). The user-agent string SemrushBot is verifiable via reverse-DNS lookup on the crawling IP addresses. You can safely allow it unless you have a specific reason to block (e.g., AI training opt-out or SEO tool visibility).

Verify by reverse-DNS lookup: legitimate SemrushBot requests resolve to semrush's domain.

What does SemrushBot do?

Understanding SemrushBot's purpose helps you decide whether to allow or block it.

Analyzes website structure and SEO health
Tracks backlinks and referring domains
Monitors keyword rankings and competitor analysis
Crawls sites for technical SEO audits
Generates reports for SEO professionals

Frequently Asked Questions

What is the official user-agent string for SemrushBot?

The official user-agent string for SemrushBot is: SemrushBot. 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 by performing a reverse-DNS lookup on the source IP - legitimate bots resolve back to their operator's domain.

Is SemrushBot safe?

Yes, SemrushBot is a **safe and legitimate** crawler. It is operated by Semrush, which publicly documents its crawler at an official URL and follows the Robots Exclusion Protocol (RFC 9309). The user-agent string SemrushBot is verifiable via reverse-DNS lookup on the crawling IP addresses. You can safely allow it unless you have a specific reason to block (e.g., AI training opt-out or SEO tool visibility).

Will blocking SemrushBot hurt my SEO?

❓ **Impact Unknown** - The SEO consequences of blocking SemrushBot are not fully documented. Before blocking, check your analytics to confirm whether this bot generates referral traffic, review your server logs for crawl frequency, and test in a staging environment if possible.

How do I block SemrushBot in robots.txt?

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

User-agent: SemrushBot
Disallow: /

This instructs SemrushBot 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 respect robots.txt?

Yes - SemrushBot is a well-behaved bot operated by Semrush. It fetches and parses /robots.txt before crawling any page, following RFC 9309.

How do I verify if SemrushBot is crawling my site?

Search your web server access logs for the string SemrushBot (case-insensitive grep: grep -i "SemrushBot" /var/log/nginx/access.log). You can also check Google Search Console → Coverage → Crawl Stats for Googlebot variants. For SemrushBot specifically, filter by user-agent in your log analysis tool (GoAccess, AWStats, etc.).

What is the crawl frequency of SemrushBot?

SemrushBot crawls at a moderate rate. If you notice excessive traffic in your logs, you can add a Crawl-delay directive:

User-agent: SemrushBot
Crawl-delay: 10

(10 second delay between requests).

Can I block SemrushBot from specific pages only?

Yes. Instead of a global Disallow: / you can restrict SemrushBot to specific paths:

User-agent: SemrushBot
Disallow: /private/
Disallow: /staging/
Allow: /

This allows SemrushBot 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?

There are two main reasons to block SemrushBot: 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.