Safe Official docs Search Engines

Yandex Object Answer API

Operated by Yandex

Quick Facts

User-Agent:
YandexOntoDBAPI
Category:
Search Engines
Operator:
Yandex
Safety:
Safe
Blocking Impact:
Low - No SEO ranking impact
SEO Impact Score:
2/10
Official docs:
yandex.com

Confirmed by the operator

Yandex names YandexOntoDBAPI on its own documentation page, linked above. The token, purpose and robots.txt behaviour on this profile come from that page, re-checked on October 19, 2026.

What is Yandex Object Answer API?

Yandex Object Answer API is an on-demand AI fetcher operated by Yandex. It retrieves a page only when a user explicitly asks an AI assistant or agent to read, summarize, or act on a specific URL. Because it is triggered by real user intent rather than bulk crawling, blocking it mainly prevents users from pulling your content into Yandex's assistant.

Yandex Object Answer API is an on-demand AI fetcher operated by Yandex. It retrieves a page only when a user explicitly asks an AI assistant or agent to read, summarize, or act on a specific URL. Because it is triggered by real user intent rather than bulk crawling, blocking it mainly prevents users from pulling your content into Yandex's assistant.
Yandex Object Answer API uses the user-agent token YandexOntoDBAPI. You can control it via robots.txt, meta tags (noai), or the emerging llms.txt standard. Robots.txt is voluntary; for hard enforcement, combine it with server-level IP blocking.

What happens if you block Yandex Object Answer API?

🔶 AI Visibility Trade-off - Blocking Yandex Object Answer API will not hurt Google or Bing rankings, but it can remove your content from AI search answers and assistant citations powered by this crawler. Block only if you have a deliberate reason.
Generally safe to allow; provides legitimate crawling value.

How to block Yandex Object Answer API with robots.txt

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

Block completely (robots.txt)
User-agent: YandexOntoDBAPI Disallow: /
Allow all (robots.txt)
User-agent: YandexOntoDBAPI Allow: /
Block private only (robots.txt)
User-agent: YandexOntoDBAPI Disallow: /private/ Disallow: /api/ Disallow: /admin/ Allow: /
Nginx server block
# Nginx: Hard-block Yandex Object Answer API if ($http_user_agent ~* "YandexOntoDBAPI") { return 403 "Bot blocked"; }
Apache .htaccess
# Apache: Hard-block Yandex Object Answer API SetEnvIfNoCase User-Agent "YandexOntoDBAPI" 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 Yandex Object Answer API safe to allow?

Yes, Yandex Object Answer API is a safe and legitimate crawler operated by Yandex. It follows the Robots Exclusion Protocol (RFC 9309) and can be controlled with standard robots.txt rules.
Verify by reverse-DNS lookup: legitimate Yandex Object Answer API requests resolve to Yandex's domain.

What does Yandex Object Answer API do?

Understanding Yandex Object Answer API's purpose helps you decide whether to allow or block it.

  • Fetches a page only when a user asks an AI assistant to read it
  • Summarizes or extracts the URL the user provided
  • Triggered by real user intent, not bulk crawling
  • Low traffic volume compared with training crawlers
  • Blocking it prevents users from pulling your content into the assistant

Yandex Object Answer API in context

Yandex Object Answer API is a user-triggered agent operated by Yandex. In plain terms, it fetches a page when a person asks an assistant or app to open it. Our database files it under search engines and ranks it Tier 3, mid-priority crawlers with a clear purpose but a smaller audience. 62 of the 63 search engines in our database share this tier.

Its safety rating is safe and its blocking impact is not documented. So the decision about Yandex Object Answer API rests on what you want from Yandex, not on its behaviour. How we rate safety and impact.

How site owners treat Yandex Object Answer API

Our robots.txt study of the Tranco top 10,000 did not track YandexOntoDBAPI as a named token, so we do not publish an adoption figure for it. If you run a large site, your own logs are the best evidence of how often it visits.

Does it follow robots.txt?

Yandex Object Answer API's operator does not clearly document how it treats robots.txt. Write the Yandex Object Answer API rule anyway, then confirm in your logs that its requests stop.

Yandex crawlers and close alternatives

Yandex Object Answer API is one of 39 Yandex crawlers in our database. A User-agent: YandexOntoDBAPI group controls Yandex Object Answer API only; the other Yandex tokens below need their own lines.

  • YandexOntoDBAPI: this crawler (Tier 3)
  • YaDirectFetcher: Yandex Direct Fetcher, checks pages for an SEO, uptime or analytics service (Tier 3)
  • Yandex: Yandex, builds a search or answer index (Tier 3)
  • YandexAccessibilityBot: Yandex Accessibility, builds a search or answer index (Tier 3)
  • YandexAdditional: YandexAdditional, builds a search or answer index (Tier 3)
  • YandexAdditionalBot: YandexAdditionalBot, builds a search or answer index (Tier 3)
  • YandexAdNet: Yandex Advertising Network, checks pages for an SEO, uptime or analytics service (Tier 3)
  • YandexBlogs: Yandex Blogs, builds a search or answer index (Tier 3)
  • YandexBot: Yandex Search, builds a search or answer index (Tier 3)

To give Yandex Object Answer API the same answer as its siblings, stack User-agent: YandexOntoDBAPI with their lines above one set of rules; to treat Yandex Object Answer API differently, give it its own group.

No other crawler in our search engines category has exactly the same purpose, which makes Yandex Object Answer API an unusual case: decide about it on its own merits.

We first recorded YandexOntoDBAPI on September 22, 2026. Yandex documents it on yandex.com, and we recheck that page before each release.

Which rule Yandex Object Answer API actually follows

Yandex Object Answer API reads exactly one group in robots.txt, the most specific one that names YandexOntoDBAPI, and never combines rules across groups. This short file shows the trap:

User-agent: *
Disallow: /private/

User-agent: YandexOntoDBAPI
Disallow: /drafts/
  1. Find the group. Yandex Object Answer API looks for a group naming YandexOntoDBAPI. One exists, so it ignores User-agent: * completely.
  2. Apply only that group. It is refused /drafts/ and nothing else.
  3. The surprise. /private/ is open to Yandex Object Answer API, because that rule lives in the * group it no longer reads. To keep it out of both, repeat Disallow: /private/ inside its own group.
Test yourself: does a rule under User-agent: * apply to Yandex Object Answer API if the file also has a User-agent: YandexOntoDBAPI group?

No. Once a group names it, Yandex Object Answer API reads only that group. Put every rule you want it to follow inside its own group.

Test yourself: will blocking Yandex Object Answer API remove your pages from AI answers?

Often, yes. Yandex Object Answer API is a user-triggered agent, so pages it cannot fetch can drop out of the answers or results it supports.

Test yourself: is User-agent: yandexontodbapi the same as User-agent: YandexOntoDBAPI?

Yes. RFC 9309 makes user-agent matching case-insensitive. Paths are a different story: Disallow: /Blog/ does not block /blog/.

Should you allow Yandex Object Answer API? Decide by situation

Recommended setting for Yandex Object Answer API by type of site
If you are...Recommended setting
You publish content and want AI answers to cite itAllow it. Yandex Object Answer API fetches pages for answers, so blocking it can remove you from them.
You license content and want to stop AI trainingBlocking it does not stop training, because Yandex Object Answer API is a user-triggered agent. Block the operator's training crawler instead.
You run an online shopAllow it unless it is overloading your servers.
Your server is under load from botsRate-limit before blocking. It is rated safe in our database.

Check Yandex Object Answer API on your own site

  1. Open /robots.txt on your domain and search for YandexOntoDBAPI. If it is not named, it follows User-agent: *.
  2. List the Disallow lines in the group Yandex Object Answer API follows and test your key URLs against them; the longest match wins, and Allow wins a tie.
  3. Look beyond the file. A firewall or bot manager can refuse Yandex Object Answer API even when robots.txt allows it, and that never shows in the file.
  4. Run our crawler access checker to see how Yandex Object Answer API and every other crawler we track are treated in one pass, including firewall refusals.

Common mistakes with Yandex Object Answer API

The errors we see most often with Yandex Object Answer API in the files and firewalls we test:

  1. Assuming a robots.txt rule will stop Yandex Object Answer API. User-triggered fetches act for a person, and some operators say robots.txt may not apply to them. Check the operator's statement above.
  2. Blocking Yandex Object Answer API as if it were a bulk crawler. It fetches one page because a person asked; blocking it means that person's assistant cannot read your page.
  3. Counting Yandex Object Answer API visits as crawl volume. Each request maps to a real user question, which makes the paths it requests a useful signal of what people ask about you.

All three hide inside a file that looks correct, so check Yandex Object Answer API from outside after every change.

Spotting Yandex Object Answer API in your logs

robots.txt says what Yandex Object Answer API may do; your access logs show what it actually did.

Count requests

On a server with standard Nginx or Apache logs, this counts matching requests per day (adjust the log path for your host):

grep -iE "YandexOntoDBAPI" /var/log/nginx/access.log \
  | awk '{print $4}' | cut -d: -f1 | sort | uniq -c

And this shows which paths it requested most, which is the quickest way to see whether your Disallow lines are being respected:

grep -iE "YandexOntoDBAPI" /var/log/nginx/access.log \
  | awk '{print $7}' | sort | uniq -c | sort -rn | head -20

Check the requests are genuine

Anyone can send the Yandex Object Answer API user-agent, so confirm the source before acting on a match:

  • YandexOntoDBAPI: we hold no published IP list, so use reverse DNS where the operator documents a hostname and treat an unverifiable Yandex Object Answer API request with caution.

Frequently Asked Questions

What is the official user-agent string for Yandex Object Answer API?
The official user-agent string for Yandex Object Answer API is: YandexOntoDBAPI. Use this exact string in robots.txt, Nginx, Apache, or Cloudflare firewall rules to target this bot. Matching in robots.txt is case-insensitive. Verify a request genuinely comes from Yandex Object Answer API by performing a reverse-DNS lookup on the source IP.
Is Yandex Object Answer API safe?
Yes, Yandex Object Answer API is a safe and legitimate crawler operated by Yandex. It follows the Robots Exclusion Protocol (RFC 9309) and can be controlled with standard robots.txt rules.
Will blocking Yandex Object Answer API hurt my SEO?
🔶 AI Visibility Trade-off - Blocking Yandex Object Answer API will not hurt Google or Bing rankings, but it can remove your content from AI search answers and assistant citations powered by this crawler. Block only if you have a deliberate reason.
How do I block Yandex Object Answer API in robots.txt?
Add the following lines to your /robots.txt file:
User-agent: YandexOntoDBAPI
Disallow: /

This instructs Yandex Object Answer API not to crawl any path on your site. To block only specific sections, replace / with the path (e.g., Disallow: /blog/).
Does Yandex Object Answer API respect robots.txt?
Yandex Object Answer API is operated by Yandex and is expected to fetch and parse /robots.txt before crawling, following RFC 9309. For hard enforcement, combine robots.txt with server-level IP or user-agent blocking.
How do I verify if Yandex Object Answer API is crawling my site?
Search your web server access logs for the string YandexOntoDBAPI (case-insensitive: grep -i "YandexOntoDBAPI" /var/log/nginx/access.log). Filter by user-agent in your log analytics tool (GoAccess, AWStats, etc.).

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