SemrushBot is the crawler for Semrush, a comprehensive digital marketing platform used by millions of marketers globally. The bot collects data for various Semrush tools including organic research, backlink analytics, and competitive analysis. SemrushBot crawls websites to understand their SEO performance, track rankings, and analyze competitive landscapes. The crawler operates at scale, processing billions of URLs to maintain fresh data across Semrush's suite of tools. Website owners who allow SemrushBot contribute to the broader SEO community's access to market intelligence and optimization insights.
// PHP Detection for SemrushBot
function detect_semrushbot() {
$user_agent = $_SERVER['HTTP_USER_AGENT'] ?? '';
$pattern = '/SemrushBot/i';
if (preg_match($pattern, $user_agent)) {
// Log the detection
error_log('SemrushBot 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($_SERVER['REQUEST_URI']) . '.html');
exit;
}
return true;
}
return false;
}
# Python/Flask Detection for SemrushBot
import re
from flask import request, make_responsedef detect_semrushbot():
user_agent = request.headers.get('User-Agent', '')
pattern = r'SemrushBot'
if re.search(pattern, user_agent, re.IGNORECASE):
# Create response with caching
response = make_response()
response.headers['Cache-Control'] = 'public, max-age=3600'
response.headers['X-Robots-Tag'] = 'noarchive'
return True
return False# Django Middleware
class SemrushBotMiddleware:
def __init__(self, get_response):
self.get_response = get_response
def __call__(self, request):
if self.detect_bot(request):
# Handle bot traffic
pass
return self.get_response(request)
// JavaScript/Node.js Detection for SemrushBot
const express = require('express');
const app = express();// Middleware to detect SemrushBot
function detectSemrushBot(req, res, next) {
const userAgent = req.headers['user-agent'] || '';
const pattern = /SemrushBot/i;
if (pattern.test(userAgent)) {
// Log bot detection
console.log('SemrushBot detected from IP:', req.ip);
// Set cache headers
res.set({
'Cache-Control': 'public, max-age=3600',
'X-Robots-Tag': 'noarchive'
});
// Mark request as bot
req.isBot = true;
req.botName = 'SemrushBot';
}
next();
}app.use(detectSemrushBot);
# Apache .htaccess rules for SemrushBot# Block completely
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} SemrushBot [NC]
RewriteRule .* - [F,L]# Or redirect to a static version
RewriteCond %{HTTP_USER_AGENT} SemrushBot [NC]
RewriteCond %{REQUEST_URI} !^/static/
RewriteRule ^(.*)$ /static/$1 [L]# Or set environment variable for PHP
SetEnvIfNoCase User-Agent "SemrushBot" is_bot=1# Add cache headers for this bot
<If "%{HTTP_USER_AGENT} =~ /SemrushBot/i">
Header set Cache-Control "public, max-age=3600"
Header set X-Robots-Tag "noarchive"
</If>
# Nginx configuration for SemrushBot# Map user agent to variable
map $http_user_agent $is_semrushbot {
default 0;
~*SemrushBot 1;
}server {
# Block the bot completely
if ($is_semrushbot) {
return 403;
}
# Or serve cached content
location / {
if ($is_semrushbot) {
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) {
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