SemrushBot-SI
Semrush •
Web Crawler
What is SemrushBot-SI?
Semrush identifies SemrushBot-SI as the token for On Page SEO Checker and similar tools. It is distinct from the core SemrushBot and SiteAuditBot entries. Semrush's support also describes this identity when troubleshooting inaccessible pages in On Page SEO Checker. The operator documents a robots.txt disallow rule but not a single fixed browser-style header on its bot page; the value here is the confirmed token.
User Agent String
SemrushBot-SI
How to Control SemrushBot-SI
Block Completely
To prevent SemrushBot-SI from accessing your entire website, add this to your robots.txt file:
# Block SemrushBot-SI
User-agent: SemrushBot-SI
Disallow: /
Block Specific Directories
To restrict access to certain parts of your site while allowing others:
User-agent: SemrushBot-SI
Disallow: /admin/
Disallow: /private/
Disallow: /wp-admin/
Allow: /public/
Set Crawl Delay
To slow down the crawl rate (note: not all bots respect this directive):
User-agent: SemrushBot-SI
Crawl-delay: 10
How to Verify SemrushBot-SI
Verification Method:
A user-agent string can be copied. Check source and crawl context, and escalate suspected impersonation to Semrush bot support rather than treating this token as proof.
A user-agent string can be copied. Check source and crawl context, and escalate suspected impersonation to Semrush bot support rather than treating this token as proof.
Learn more in the official documentation.
Detection Patterns
Multiple ways to detect SemrushBot-SI in your application:
Basic Pattern
/SemrushBot\-SI/i
Strict Pattern
/^SemrushBot\-SI$/
Flexible Pattern
/SemrushBot\-SI[\s\/]?[\d\.]*?/i
Vendor Match
/.*Semrush.*SemrushBot\-SI/i
Implementation Examples
// PHP Detection for SemrushBot-SI
function detect_semrushbot_si() {
$user_agent = $_SERVER['HTTP_USER_AGENT'] ?? '';
$pattern = '/SemrushBot\-SI/i';
if (preg_match($pattern, $user_agent)) {
// Log the detection
error_log('SemrushBot-SI detected from IP: ' . $_SERVER['REMOTE_ADDR']);
// Set cache headers
header('Cache-Control: public, max-age=3600');
header('X-Robots-Tag: noarchive');
// Optional: Serve cached version
if (file_exists('cache/' . md5($_SERVER['REQUEST_URI']) . '.html')) {
readfile('cache/' . md5($_SERVER['REQUEST_URI']) . '.html');
exit;
}
return true;
}
return false;
}
# Python/Flask Detection for SemrushBot-SI
import re
from flask import request, make_response
def detect_semrushbot_si():
user_agent = request.headers.get('User-Agent', '')
pattern = r'SemrushBot\-SI'
if re.search(pattern, user_agent, re.IGNORECASE):
# Create response with caching
response = make_response()
response.headers['Cache-Control'] = 'public, max-age=3600'
response.headers['X-Robots-Tag'] = 'noarchive'
return True
return False
# Django Middleware
class semrushbot_siMiddleware:
def __init__(self, get_response):
self.get_response = get_response
def __call__(self, request):
if self.detect_bot(request):
# Handle bot traffic
pass
return self.get_response(request)
// JavaScript/Node.js Detection for SemrushBot-SI
const express = require('express');
const app = express();
// Middleware to detect SemrushBot-SI
function detect_semrushbot_si(req, res, next) {
const userAgent = req.headers['user-agent'] || '';
const pattern = /SemrushBot\-SI/i;
if (pattern.test(userAgent)) {
// Log bot detection
console.log('SemrushBot-SI detected from IP:', req.ip);
// Set cache headers
res.set({
'Cache-Control': 'public, max-age=3600',
'X-Robots-Tag': 'noarchive'
});
// Mark request as bot
req.isBot = true;
req.botName = 'SemrushBot-SI';
}
next();
}
app.use(detect_semrushbot_si);
# Apache .htaccess rules for SemrushBot-SI
# Block completely
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} SemrushBot\-SI [NC]
RewriteRule .* - [F,L]
# Or redirect to a static version
RewriteCond %{HTTP_USER_AGENT} SemrushBot\-SI [NC]
RewriteCond %{REQUEST_URI} !^/static/
RewriteRule ^(.*)$ /static/$1 [L]
# Or set environment variable for PHP
SetEnvIfNoCase User-Agent "SemrushBot\-SI" is_bot=1
# Add cache headers for this bot
<If "%{HTTP_USER_AGENT} =~ /SemrushBot\-SI/i">
Header set Cache-Control "public, max-age=3600"
Header set X-Robots-Tag "noarchive"
</If>
# Nginx configuration for SemrushBot-SI
# Map user agent to variable
map $http_user_agent $is_semrushbot_si {
default 0;
~*SemrushBot\-SI 1;
}
server {
# Block the bot completely
if ($is_semrushbot_si) {
return 403;
}
# Or serve cached content
location / {
if ($is_semrushbot_si) {
root /var/www/cached;
try_files $uri $uri.html $uri/index.html @backend;
}
try_files $uri @backend;
}
# Add headers for bot requests
location @backend {
if ($is_semrushbot_si) {
add_header Cache-Control "public, max-age=3600";
add_header X-Robots-Tag "noarchive";
}
proxy_pass http://backend;
}
}
Should You Block This Bot?
Recommendations based on your website type:
| Site Type | Recommendation | Reasoning |
|---|---|---|
| E-commerce | Optional | Evaluate based on bandwidth usage vs. benefits |
| Blog/News | Allow | Increases content reach and discoverability |
| SaaS Application | Block | No benefit for application interfaces; preserve resources |
| Documentation | Selective | Allow for public docs, block for internal docs |
| Corporate Site | Limit | Allow for public pages, block sensitive areas like intranets |
Advanced robots.txt Configurations
E-commerce Site Configuration
User-agent: SemrushBot-SI
Crawl-delay: 5
Disallow: /cart/
Disallow: /checkout/
Disallow: /my-account/
Disallow: /api/
Disallow: /*?sort=
Disallow: /*?filter=
Disallow: /*&page=
Allow: /products/
Allow: /categories/
Sitemap: https://example.com/sitemap.xml
Publishing/Blog Configuration
User-agent: SemrushBot-SI
Crawl-delay: 10
Disallow: /wp-admin/
Disallow: /drafts/
Disallow: /preview/
Disallow: /*?replytocom=
Allow: /
SaaS/Application Configuration
User-agent: SemrushBot-SI
Disallow: /app/
Disallow: /api/
Disallow: /dashboard/
Disallow: /settings/
Allow: /
Allow: /pricing/
Allow: /features/
Allow: /docs/
Quick Reference
User Agent Match
SemrushBot-SI
Robots.txt Name
SemrushBot-SI
Category
seo
Respects robots.txt
Yes
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