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YandexAdditional

Operated by Yandex

Quick Facts

User-Agent:YandexAdditional
Category:Search Engines
Operator:Yandex
Safety:Safe
Blocking Impact:Critical — Blocking removes you from search results
SEO Impact Score:10/10

What is YandexAdditional?

A supplementary crawler used by Yandex for specific indexing tasks that may not be covered by the main YandexBot.

A supplementary crawler used by Yandex for specific indexing tasks that may not be covered by the main YandexBot. YandexAdditional is a production-grade search engine crawler operated by Yandex. It uses a distributed crawl infrastructure that respects crawl-delay directives, follows RFC 9309 (robots.txt) spec, and processes Sitemaps to prioritise fresh content. The user-agent string YandexAdditional must be whitelisted if your site uses rate-limiting or WAF rules. Blocking impact is Critical — Blocking removes you from search results.

What happens if you block YandexAdditional?

⛔ **Critical Impact** — Blocking YandexAdditional will stop Yandex from crawling and indexing your pages. Within days or weeks you may see pages drop out of Yandex's search index entirely, resulting in a significant loss of organic search traffic. This is the most severe possible SEO consequence. Only do this intentionally, for example if you are migrating to a different search engine or decommissioning a domain. If you accidentally blocked YandexAdditional, remove the rule immediately and request re-indexing via Yandex's webmaster tools.
Never block — it will remove your site from major search results.

How to block YandexAdditional with robots.txt

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

Block completely (robots.txt)
User-agent: YandexAdditional Disallow: /
Allow all (robots.txt)
User-agent: YandexAdditional Allow: /
Block private only (robots.txt)
User-agent: YandexAdditional Disallow: /private/ Disallow: /api/ Disallow: /admin/ Allow: /
Nginx server block
# Nginx: Hard-block YandexAdditional if ($http_user_agent ~* "YandexAdditional") { return 403 "Bot blocked"; }
Apache .htaccess
# Apache: Hard-block YandexAdditional SetEnvIfNoCase User-Agent "YandexAdditional" bad_bot Order Allow,Deny Allow from all Deny from env=bad_bot
Meta robots tag
<meta name="robots" content="noindex, nofollow">
X-Robots-Tag header
X-Robots-Tag: noindex, nofollow

Is YandexAdditional safe to allow?

Yes, YandexAdditional is a **safe and legitimate** crawler. It is operated by Yandex, which publicly documents its crawler at an official URL and follows the Robots Exclusion Protocol (RFC 9309). The user-agent string YandexAdditional 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 YandexAdditional requests resolve to yandex's domain.

What does YandexAdditional do?

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

Frequently Asked Questions

What is the official user-agent string for YandexAdditional?
The official user-agent string for YandexAdditional is: YandexAdditional. 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 YandexAdditional by performing a reverse-DNS lookup on the source IP — legitimate bots resolve back to their operator's domain.
Is YandexAdditional safe?
Yes, YandexAdditional is a **safe and legitimate** crawler. It is operated by Yandex, which publicly documents its crawler at an official URL and follows the Robots Exclusion Protocol (RFC 9309). The user-agent string YandexAdditional 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 YandexAdditional hurt my SEO?
⛔ **Critical Impact** — Blocking YandexAdditional will stop Yandex from crawling and indexing your pages. Within days or weeks you may see pages drop out of Yandex's search index entirely, resulting in a significant loss of organic search traffic. This is the most severe possible SEO consequence. Only do this intentionally, for example if you are migrating to a different search engine or decommissioning a domain. If you accidentally blocked YandexAdditional, remove the rule immediately and request re-indexing via Yandex's webmaster tools.
How do I block YandexAdditional in robots.txt?
Add the following lines to your /robots.txt file:
User-agent: YandexAdditional
Disallow: /
This instructs YandexAdditional 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 YandexAdditional respect robots.txt?
Yes — YandexAdditional is a well-behaved bot operated by Yandex. It fetches and parses /robots.txt before crawling any page, following RFC 9309.
How do I verify if YandexAdditional is crawling my site?
Search your web server access logs for the string YandexAdditional (case-insensitive grep: grep -i "YandexAdditional" /var/log/nginx/access.log). You can also check Google Search Console → Coverage → Crawl Stats for Googlebot variants. For YandexAdditional specifically, filter by user-agent in your log analysis tool (GoAccess, AWStats, etc.).
What is the crawl frequency of YandexAdditional?
Critical-impact search crawlers like YandexAdditional typically crawl popular pages daily and less popular pages weekly. You can manage crawl rate via the crawl-delay directive or via the search console.
Can I block YandexAdditional from specific pages only?
Yes. Instead of a global Disallow: / you can restrict YandexAdditional to specific paths:
User-agent: YandexAdditional
Disallow: /private/
Disallow: /staging/
Allow: /
This allows YandexAdditional everywhere except the listed paths. Path matching in robots.txt uses prefix matching — Disallow: /private/ blocks /private/page.html but NOT /public/private/.
How do I check if YandexAdditional is blocked by my robots.txt?
Use Google's robots.txt Tester in Search Console, or a third-party checker to simulate a YandexAdditional request. You can also manually check by opening https://aicrawlercheck.com/robots.txt and scanning for YandexAdditional entries. If a block exists, immediately test it against your most important URLs using the Google Search Console URL Inspection tool.
My site is blocked by YandexAdditional in Search Console — what do I do?
1. Open yourdomain.com/robots.txt and look for any User-agent: YandexAdditional or User-agent: * Disallow rules covering your key pages. 2. Remove or restrict the blocking rules. 3. Validate via Google Search Console → robots.txt Tester. 4. Request re-indexing using the URL Inspection tool. 5. Wait 1-2 weeks for re-crawl. Monitor Coverage report for recovery.

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