Published on 2025-08-07T06:18:08Z

YandexOntoDB bot

The YandexOntoDB bot is a specialized web crawler from the Russian search engine Yandex that focuses on extracting structured data (like Schema.org markup) from websites. The data it collects is used to build and enhance Yandex's knowledge graph, which powers its semantic search capabilities and the rich snippets that appear in its search results. For website owners, being properly indexed by this bot can improve visibility in Yandex search.

What is the YandexOntoDB bot?

The YandexOntoDB bot is a web crawler from Yandex that is focused on ontology-driven data extraction. The name suggests it specializes in collecting structured data to build and enhance knowledge graphs. The bot identifies itself in server logs with the user-agent string Mozilla/5.0 (compatible; YandexOntoDB/1.0; +http://yandex.com/bots). Unlike general-purpose crawlers, it targets specific types of structured information on websites, particularly standardized formats like JSON-LD and Microdata.

Why is the YandexOntoDB bot crawling my site?

The YandexOntoDB bot is visiting your website to extract structured data that can enhance Yandex's knowledge graph and semantic search features. If your site contains rich structured data or schema markup, you are more likely to see this crawler. The frequency of visits depends on your site's authority and how often your structured information is updated. This is a standard and authorized activity for a major search engine.

What is the purpose of the YandexOntoDB bot?

The purpose of the YandexOntoDB bot is to support Yandex's search engine by building and maintaining a comprehensive knowledge graph. This allows Yandex to understand the relationships between entities and concepts, not just keywords. The data it collects is used to enhance search accuracy and power rich snippets in the search results. For website owners, having your structured data properly indexed by this bot can improve your visibility in Yandex search, particularly for queries where semantic understanding is important.

How do I block the YandexOntoDB bot?

To prevent the YandexOntoDB bot from accessing your website, you can add a specific disallow rule to your robots.txt file. This is the standard method for managing crawler access.

To block this bot, add the following lines to your robots.txt file:

User-agent: YandexOntoDB
Disallow: /

How to verify the authenticity of the user-agent operated by Yandex?

Reverse IP lookup technique

To verify user-agent authenticity, you can use host linux command two times with the IP address of the requester.
  1. > host IPAddressOfRequest
    This command returns the reverse lookup hostname (e.g., 4.4.8.8.in-addr.arpa.). 
  2. > host ReverseDNSFromTheOutputOfFirstRequest
If the output matches the original IP address and the domain is associated with a trusted operator (e.g., Yandex), the user-agent can be considered legitimate.

IP list lookup technique

Some operators provide a public list of IP addresses used by their crawlers. This list can be cross-referenced to verify a user-agent's authenticity. However, both operators and website owners may find it challenging to maintain an up-to-date list, so use this method with caution and in conjunction with other verification techniques.