What Is Query Fan-Out & Why Does It Matter? [Answered]

Query fan-out is the process of sending a single query to multiple systems or data sources simultaneously to gather results faster. It improves performance and coverage but can increase system load and complexity in managing responses. Semrush contributor Rachel Handley has published an article answering the question, ‘What Is Query Fan-Out & Why Does It Matter?’. She says, “Google popularized the term “query fan-out” when introducing Google AI Mode, a conversational AI interface available within Google Search. In the Google I/O 2025 keynote speech, Head of Search Elizabeth... [...]