What is query fan-out? How AI search splits one question

Query fan-out is how an AI search system turns the one question you type into several related searches, one per subtopic, and then merges the results into a single answer. Google uses the term for its own AI Mode. We could not verify an equivalent description of the same name from a primary source for other products.

What does query fan-out mean?

"Fan-out" means spreading from one point in many directions. Here the point is the user's single question, and the directions are the sub-searches derived from it.

Google describes the technique in its 5 March 2025 post introducing AI Mode: the system issues "multiple related searches concurrently across subtopics and multiple data sources and then brings those results together to provide an easy-to-understand response". The post says this gives more breadth and depth than a traditional search. In the Google I/O announcement of 20 May 2025, Google wrote that AI Mode breaks your question down into subtopics and issues a multitude of queries simultaneously.

A made-up example (we are not showing Google's real sub-searches, because Google does not show them to users or site owners; the example only illustrates the logic):

One sentence typed into a single search box becomes several separate questions in the background, and pages are found and picked against those sub-questions.

Which search products use query fan-out?

Only Google is verified:

• AI Mode. Google presents the technique as the basis of AI Mode (5 March and 20 May 2025).
• AI Overviews. Google's Search Central documentation says both AI Overviews and AI Mode "may use" the technique, so it does not claim every answer uses it. The same page says the two features may use different models and techniques, so the answers and links they show will vary.
• Deep Search. According to the 20 May 2025 announcement, it uses the same technique "taken to the next level": it can issue hundreds of searches and produce a cited report.
• Gemini 3. On 18 November 2025 Google wrote that Gemini 3 arrived in AI Mode and gave the technique "a major upgrade": it can run more searches, and because the model understands intent better, it can find content it may have missed before.

For ChatGPT, Perplexity, Copilot and Claude, a description of the same name could not be verified. OpenAI's help pages returned 403 to our automated request during this check and could not be opened. We make no claim here about whether or how those products split questions.

What does query fan-out mean for a site owner?

The sentences in Google's documentation are short:

• To be shown as a supporting link in AI Overviews or AI Mode, a page must be indexed and eligible to be shown in Google Search with a snippet. There are no additional technical requirements.
• No specific optimization is required for these features; the existing SEO fundamentals apply (crawling allowed in robots.txt and by any CDN, internal links, important content in text form, structured data that matches the visible text).
• You do not need new machine-readable files, "AI text files" or markup, and there is no special schema.org structured data to add.
• Indexing and serving are not guaranteed.

The documentation (last updated 10 December 2025) gives no separate advice for query fan-out. The section below is therefore our interpretation, not Google's.

If my page answers the sub-questions, am I more likely to be picked?

Our interpretation: possibly. It is not proven. We found no sentence in Google's documentation saying so, and we have no measurement. The logic is that if the system splits a question into parts and searches for the parts, a page that answers one part clearly may be easier to find for that search. Low-cost steps to try:

1. Write out the sub-questions. List what a person on the topic would ask next: definition, how to do it, cost, time, comparison, common mistakes, anything specific to Turkey.
2. Make each sub-question a question heading. Put a one- or two-sentence plain answer right under it. How to write that structure: Make the first paragraph the answer: short-answer blocks
3. Put the answer in the page text. Google recommends that important content be available in textual form and that structured data match the visible text.
4. A separate page per sub-question is not required. If one page answers several related sub-questions, keep them together; separate, independent topics deserve separate pages. Connect pages with internal links.
5. Write names, numbers and dates plainly. Sub-searches usually look for a specific piece of information. Write the service's name instead of "this service" and the year instead of "last year", so each part stands on its own.

Can I see the sub-searches?

Google's Search Central documentation describes no report that shows site owners the sub-searches. According to it, clicks and impressions from AI features are counted in the Search Console Performance report under the "Web" search type. So you cannot read from it which sub-search picked you; you only see the total effect.

To guess which questions get asked, you can use your own customer questions, support logs and the "people also ask" boxes of search engines. These are guesses, not Google's real sub-searches.

How is query fan-out different from GEO?

GEO (Generative Engine Optimization) is the general name for work aimed at appearing in AI answers. Query fan-out is one step used while those answers are produced. Our article on what Google says GEO is: What is GEO, and how is it different from SEO? On how a brand is mentioned and measured in AI answers: How does your brand appear in ChatGPT and AI answers, and how do you measure it?

Ruescan is Rueseo's site scanner. One of its 275 signals checks whether the page has question-style headings. It is counted as an "opportunity"; missing it is not an error (signal glossary).

Frequently asked questions