YaDirectFetcher
Yandex •
Web Crawler
What is YaDirectFetcher?
Yandex says YaDirectFetcher downloads target pages of ads to check availability and topic before ads are placed in search results or on partner sites. The official bot table explicitly says it does not use robots.txt and ignores directives aimed at it. This is an advertising check, not YandexBot web indexing and not the YandexDirectDyn banner generator.
User Agent String
Mozilla/5.0 (compatible; YaDirectFetcher/1.0; Dyatel; +http://yandex.com/bots)
How to Control YaDirectFetcher
Block Completely
To prevent YaDirectFetcher from accessing your entire website, add this to your robots.txt file:
# Block YaDirectFetcher
User-agent: YaDirectFetcher
Disallow: /
Block Specific Directories
To restrict access to certain parts of your site while allowing others:
User-agent: YaDirectFetcher
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: YaDirectFetcher
Crawl-delay: 10
How to Verify YaDirectFetcher
Verification Method:
Use Yandex's forward-confirmed reverse-DNS procedure; the Dyatel user-agent component alone is not proof of origin.
Use Yandex's forward-confirmed reverse-DNS procedure; the Dyatel user-agent component alone is not proof of origin.
Learn more in the official documentation.
Detection Patterns
Multiple ways to detect YaDirectFetcher in your application:
Basic Pattern
/YaDirectFetcher/i
Strict Pattern
/^Mozilla\/5\.0 \(compatible; YaDirectFetcher\/1\.0; Dyatel; \+http\:\/\/yandex\.com\/bots\)$/
Flexible Pattern
/YaDirectFetcher[\s\/]?[\d\.]*?/i
Vendor Match
/.*Yandex.*YaDirectFetcher/i
Implementation Examples
// PHP Detection for YaDirectFetcher
function detect_yadirectfetcher() {
$user_agent = $_SERVER['HTTP_USER_AGENT'] ?? '';
$pattern = '/YaDirectFetcher/i';
if (preg_match($pattern, $user_agent)) {
// Log the detection
error_log('YaDirectFetcher 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($_SERVER['REQUEST_URI']) . '.html');
exit;
}
return true;
}
return false;
}
# Python/Flask Detection for YaDirectFetcher
import re
from flask import request, make_response
def detect_yadirectfetcher():
user_agent = request.headers.get('User-Agent', '')
pattern = r'YaDirectFetcher'
if re.search(pattern, user_agent, re.IGNORECASE):
# Create response with caching
response = make_response()
response.headers['Cache-Control'] = 'public, max-age=3600'
response.headers['X-Robots-Tag'] = 'noarchive'
return True
return False
# Django Middleware
class yadirectfetcherMiddleware:
def __init__(self, get_response):
self.get_response = get_response
def __call__(self, request):
if self.detect_bot(request):
# Handle bot traffic
pass
return self.get_response(request)
// JavaScript/Node.js Detection for YaDirectFetcher
const express = require('express');
const app = express();
// Middleware to detect YaDirectFetcher
function detect_yadirectfetcher(req, res, next) {
const userAgent = req.headers['user-agent'] || '';
const pattern = /YaDirectFetcher/i;
if (pattern.test(userAgent)) {
// Log bot detection
console.log('YaDirectFetcher detected from IP:', req.ip);
// Set cache headers
res.set({
'Cache-Control': 'public, max-age=3600',
'X-Robots-Tag': 'noarchive'
});
// Mark request as bot
req.isBot = true;
req.botName = 'YaDirectFetcher';
}
next();
}
app.use(detect_yadirectfetcher);
# Apache .htaccess rules for YaDirectFetcher
# Block completely
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} YaDirectFetcher [NC]
RewriteRule .* - [F,L]
# Or redirect to a static version
RewriteCond %{HTTP_USER_AGENT} YaDirectFetcher [NC]
RewriteCond %{REQUEST_URI} !^/static/
RewriteRule ^(.*)$ /static/$1 [L]
# Or set environment variable for PHP
SetEnvIfNoCase User-Agent "YaDirectFetcher" is_bot=1
# Add cache headers for this bot
<If "%{HTTP_USER_AGENT} =~ /YaDirectFetcher/i">
Header set Cache-Control "public, max-age=3600"
Header set X-Robots-Tag "noarchive"
</If>
# Nginx configuration for YaDirectFetcher
# Map user agent to variable
map $http_user_agent $is_yadirectfetcher {
default 0;
~*YaDirectFetcher 1;
}
server {
# Block the bot completely
if ($is_yadirectfetcher) {
return 403;
}
# Or serve cached content
location / {
if ($is_yadirectfetcher) {
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_yadirectfetcher) {
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: YaDirectFetcher
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: YaDirectFetcher
Crawl-delay: 10
Disallow: /wp-admin/
Disallow: /drafts/
Disallow: /preview/
Disallow: /*?replytocom=
Allow: /
SaaS/Application Configuration
User-agent: YaDirectFetcher
Disallow: /app/
Disallow: /api/
Disallow: /dashboard/
Disallow: /settings/
Allow: /
Allow: /pricing/
Allow: /features/
Allow: /docs/
Quick Reference
User Agent Match
YaDirectFetcher
Robots.txt Name
YaDirectFetcher
Category
other
Respects robots.txt
May not respect
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