WebPageTest
WebPageTest •
Since 2008
Quick Actions
Official Docs
What is WebPageTest?
WebPageTest bot is the crawler for the popular open-source web performance testing tool. Originally developed by AOL and now maintained by Catchpoint, WebPageTest provides detailed performance metrics including Core Web Vitals, waterfall charts, and filmstrip views. The bot can simulate various connection speeds, devices, and geographic locations to provide comprehensive performance testing. WebPageTest is widely used by performance engineers and developers for its detailed metrics and ability to test from multiple global locations. The service offers both public and private testing instances.
User Agent String
Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36 WebPageTest
How to Control WebPageTest
Block Completely
To prevent WebPageTest from accessing your entire website, add this to your robots.txt file:
# Block WebPageTest
User-agent: WebPageTest
Disallow: /
Block Specific Directories
To restrict access to certain parts of your site while allowing others:
User-agent: WebPageTest
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: WebPageTest
Crawl-delay: 10
How to Verify WebPageTest
Verification Method:
WebPageTest identification in user agent
WebPageTest identification in user agent
Learn more in the official documentation.
Detection Patterns
Multiple ways to detect WebPageTest in your application:
Basic Pattern
/WebPageTest/i
Strict Pattern
/^Mozilla/5\.0 \(X11; Linux x86_64\) AppleWebKit/537\.36 \(KHTML, like Gecko\) Chrome/125\.0\.0\.0 Safari/537\.36 WebPageTest$/
Flexible Pattern
/WebPageTest[\s\/]?[\d\.]*?/i
Vendor Match
/.*WebPageTest.*WebPageTest/i
Implementation Examples
// PHP Detection for WebPageTest
function detect_webpagetest() {
$user_agent = $_SERVER['HTTP_USER_AGENT'] ?? '';
$pattern = '/WebPageTest/i';
if (preg_match($pattern, $user_agent)) {
// Log the detection
error_log('WebPageTest 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($_SERVER['REQUEST_URI']) . '.html');
exit;
}
return true;
}
return false;
}
# Python/Flask Detection for WebPageTest
import re
from flask import request, make_response
def detect_webpagetest():
user_agent = request.headers.get('User-Agent', '')
pattern = r'WebPageTest'
if re.search(pattern, user_agent, re.IGNORECASE):
# Create response with caching
response = make_response()
response.headers['Cache-Control'] = 'public, max-age=3600'
response.headers['X-Robots-Tag'] = 'noarchive'
return True
return False
# Django Middleware
class WebPageTestMiddleware:
def __init__(self, get_response):
self.get_response = get_response
def __call__(self, request):
if self.detect_bot(request):
# Handle bot traffic
pass
return self.get_response(request)
// JavaScript/Node.js Detection for WebPageTest
const express = require('express');
const app = express();
// Middleware to detect WebPageTest
function detectWebPageTest(req, res, next) {
const userAgent = req.headers['user-agent'] || '';
const pattern = /WebPageTest/i;
if (pattern.test(userAgent)) {
// Log bot detection
console.log('WebPageTest detected from IP:', req.ip);
// Set cache headers
res.set({
'Cache-Control': 'public, max-age=3600',
'X-Robots-Tag': 'noarchive'
});
// Mark request as bot
req.isBot = true;
req.botName = 'WebPageTest';
}
next();
}
app.use(detectWebPageTest);
# Apache .htaccess rules for WebPageTest
# Block completely
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} WebPageTest [NC]
RewriteRule .* - [F,L]
# Or redirect to a static version
RewriteCond %{HTTP_USER_AGENT} WebPageTest [NC]
RewriteCond %{REQUEST_URI} !^/static/
RewriteRule ^(.*)$ /static/$1 [L]
# Or set environment variable for PHP
SetEnvIfNoCase User-Agent "WebPageTest" is_bot=1
# Add cache headers for this bot
<If "%{HTTP_USER_AGENT} =~ /WebPageTest/i">
Header set Cache-Control "public, max-age=3600"
Header set X-Robots-Tag "noarchive"
</If>
# Nginx configuration for WebPageTest
# Map user agent to variable
map $http_user_agent $is_webpagetest {
default 0;
~*WebPageTest 1;
}
server {
# Block the bot completely
if ($is_webpagetest) {
return 403;
}
# Or serve cached content
location / {
if ($is_webpagetest) {
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_webpagetest) {
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: WebPageTest
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: WebPageTest
Crawl-delay: 10
Disallow: /wp-admin/
Disallow: /drafts/
Disallow: /preview/
Disallow: /*?replytocom=
Allow: /
SaaS/Application Configuration
User-agent: WebPageTest
Disallow: /app/
Disallow: /api/
Disallow: /dashboard/
Disallow: /settings/
Allow: /
Allow: /pricing/
Allow: /features/
Allow: /docs/
Quick Reference
User Agent Match
WebPageTest
Robots.txt Name
WebPageTest
Category
monitor
Respects robots.txt
May not respect
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