AI search refers to search systems that answer a query with text generated by a language model and link to the web sources the answer draws on. Examples are AI Overviews and AI Mode in Google Search, ChatGPT search and Perplexity. The result is a written answer first and a list of links second. In enterprise software, “AI search engine” can also mean semantic site search; this entry covers web search.
At a glance
- Type
- search system with an AI-generated answer and source links
- Used in
- AI Overviews, AI Mode, ChatGPT search, Perplexity, web search in Claude
- Technique at Google
- query fan-out (several related searches)
- Visible?
- for Google, impressions in the Search Console generative AI performance report (since Aug 31, 2026)
Last checked:
How does AI search work?
An AI search system combines a language model with a search index. The model turns the question into one or more search queries, retrieves matching documents and writes an answer from them. Pages that contributed appear as source links.
Google calls its version of this step query fan-out. According to Google’s documentation, AI Overviews and AI Mode issue multiple related searches across subtopics and data sources to build a response. The AI Mode help page describes it as dividing a question into subtopics and searching for each one at the same time. Users can then ask follow-up questions that build on the previous answer.
Providers outside Google run their own crawlers. OpenAI uses OAI-SearchBot to surface sites in ChatGPT search and a separate bot, GPTBot, for model training. Perplexity uses PerplexityBot to surface and link websites in its results and states that this bot is not used to train foundation models. Each of these can be controlled in robots.txt.
What does AI search mean for websites?
For Google’s AI features the entry requirements match regular search. A page must be indexed and eligible to appear with a snippet. Google says no special files or markup are needed. To limit how content is used, site owners have nosnippet, data-nosnippet, max-snippet and noindex, plus a Search Console setting introduced in 2026 that excludes a site from Google’s generative AI features.
Measurement is still thin. Google Search Console counts AI Overview and AI Mode traffic in the Web search type and, since 2026, has a Generative AI performance report with impressions per page, country and device. Queries and clicks are not broken out there. For ChatGPT, Perplexity and similar tools there is no equivalent dashboard, so companies run their own prompt sets or use tracking tools.
- OpenAI releases ChatGPT as a free research preview. The model is based on the GPT-3.5 series.Source: openai.com
- Google announces its conversational AI service Bard and opens it to trusted testers first.Source: blog.google
- Microsoft launches the new Bing with AI chat and complete answers inside search.Source: blogs.microsoft.com
- Google introduces the Search Generative Experience (SGE) as an experiment in Search Labs. At launch it is limited to the US and English.Source: blog.google
- Microsoft renames Bing Chat to Copilot. General availability follows from December 1, 2023.Source: blogs.microsoft.com
- At Google I/O, Google announces AI Overviews for everyone in the US, with more countries to follow.Source: blog.google
- Bing previews its generative search experience. At first it appears for a small share of queries only.Source: blogs.bing.com
- OpenAI tests SearchGPT as a temporary prototype with a small group of users and publishers.Source: openai.com
- AI Overviews roll out in more than 100 countries and territories. Google expects more than 1 billion monthly users.Source: blog.google
- OpenAI launches ChatGPT search, first for paying users and the SearchGPT waitlist. Answers link to their sources.Source: openai.com
- Google launches Deep Research in Gemini Advanced. It browses the web on its own and compiles a report.Source: blog.google
- ChatGPT search becomes available to all logged-in users in regions where ChatGPT is offered.Source: openai.com
- OpenAI introduces deep research in ChatGPT, starting with Pro users.Source: openai.com
- ChatGPT search becomes available without signing up in all regions where ChatGPT is offered.Source: openai.com
- Google introduces AI Mode as an experiment in Search Labs. Google One AI Premium subscribers get access first.Source: blog.google
- Anthropic adds web search with citations to Claude. It launches as a preview for paid users in the US.Source: anthropic.com
- AI Overviews launch in Germany in German and English, together with other European countries. They are shown to signed-in users aged 18 and over.Source: blog.google
- At Google I/O, Google rolls out AI Mode to everyone in the US, with no Labs sign-up needed.Source: blog.google
- AI Overviews are available in more than 200 countries and territories and in more than 40 languages.Source: blog.google
- Web search in Claude becomes available globally on all plans.Source: anthropic.com
- Data from AI Mode counts towards the totals in the Search Console Performance report.Source: developers.google.com
- AI Mode launches in Germany, Austria and Switzerland as part of an expansion to more than 40 new countries and territories.Source: blog.google
- Search Console adds dedicated performance reports for generative AI features such as AI Overviews and AI Mode, first for a subset of sites.Source: developers.google.com
- The Search Console reports on generative AI features become available to all websites worldwide.Source: developers.google.com
Dates follow the publisher's announcement; rollouts often took days or weeks. Google's English post on AI Overviews in Europe carries the US date of March 25, 2025, the German post March 26, 2025. Last checked: .
Example
Someone types “Which hiking boots work for wide feet on wet trails?” An AI search engine replies with a short explanation of last widths and waterproof membranes, a handful of models, and links to reviews and manufacturer pages. Which pages get linked depends on what the system found for each sub-question it searched.
FAQ
What is the best AI search engine? That depends on the task, and rankings of tools change quickly. For site owners the more useful question is which systems send visitors and which crawlers they need to allow.
Can I turn off AI in Google Search? AI Overviews appear automatically for some queries. According to reports, Google offers a “Web” filter that shows only links. AI Mode is a separate tab that users open on purpose.
Does AI search replace traditional search? Both run side by side. Google shows AI Overviews on the normal results page, and its AI features only cite pages from its search index.
Sources
- AI features and your website – Google Search Centraldevelopers.google.com
- Google's guide to optimizing for generative AI features on Google Search – Google Search Centraldevelopers.google.com
- Get AI-powered responses with AI Mode in Google Search – Google Search Helpsupport.google.com
- Overview of OpenAI Crawlers – OpenAIdevelopers.openai.com
- Perplexity Crawlers – Perplexity Docsdocs.perplexity.ai
- Generative AI performance report – Search Console Helpsupport.google.com
- Search generative AI features control – Search Console Help (rolled out worldwide as of 2026-08-31)support.google.com
Last updated: