Where ChatGPT, Gemini, Copilot and Perplexity get their answers

Short answer: it depends on the assistant. Gemini and Google's AI Overviews and AI Mode use the Google Search index, and Microsoft Copilot uses Bing. OpenAI (ChatGPT), Perplexity, Anthropic (Claude) and Apple (Siri) each run their own search crawler. OpenAI says ChatGPT search sometimes partners with other search providers and points to Microsoft's and Shopify's privacy policies for how those providers handle queries, but it does not name a search engine (OpenAI Help Center). Perplexity, Anthropic and Apple do not say in their documentation which search engine, if any, they also rely on.

This matters for a Luxembourg business because each assistant can only mention you if it can find you. Being well placed on Google does not automatically mean Copilot or ChatGPT can see you, and the other way round.

Which search engine does each AI assistant use?

Everything in this table comes from each provider's own help or developer pages, checked on 24 October 2026. We did not use press reports or outside tests.

Assistant	Where it looks things up	Its own crawler (robots.txt name)	Search partner named by the provider
ChatGPT (OpenAI)	ChatGPT's own search features	OAI-SearchBot	"Other search providers", unnamed; OpenAI links Microsoft's privacy statement and Shopify's privacy policy
Gemini app (Google)	The Google Search index	Google's crawlers; the Google-Extended setting controls use for training and grounding	Google Search (its own)
Google AI Overviews and AI Mode	Part of Google Search: pages must be indexed by Google	Googlebot	Google Search (its own)
Microsoft Copilot	The Bing search service	Not named on Microsoft's Copilot page	Bing (its own)
Perplexity	Perplexity's own search results	PerplexityBot	Not stated by the provider
Claude (Anthropic)	Claude's web search tool	Claude-SearchBot	Not stated by the provider for web results; image results are "powered by Bing"
Siri and Apple Intelligence	Apple's own search technology	Applebot	Not stated by the provider

Most of these assistants also have a second visitor that fetches a page only when a user asks about it, such as ChatGPT-User, Claude-User and Perplexity-User. Those are not used to decide what appears in search results.

Does ChatGPT use Google or Bing?

OpenAI does not name a search engine, but it does describe how its search works. Its help page says that "ChatGPT search sometimes partners with other search providers". When it does, it "typically rewrites your query into one or more targeted queries" that it sends to those providers, and may send more specific queries after reviewing the first results. For how those search providers process queries, the page links to Microsoft's privacy statement and Shopify's privacy policy. It does not mention Google (OpenAI Help Center).

The same help page explains how a website becomes eligible: allow OAI-SearchBot, and make sure your host or CDN allows OpenAI's published searchbot IP addresses. It adds that ChatGPT ranks results using multiple factors and that "Placement is not guaranteed" (OpenAI Help Center). OpenAI's crawler page explains that OAI-SearchBot is used to show websites in the search results of ChatGPT's search features, and that sites which block it will not appear in ChatGPT search answers, although they can still show up as plain navigational links (OpenAI). OpenAI adds that a change to robots.txt takes about 24 hours to reach its search systems.

The same page lists two other OpenAI visitors. GPTBot collects content that may be used to train OpenAI's models, and ChatGPT-User visits a page when a user's request calls for it; OpenAI says ChatGPT-User is not used to decide what appears in search. OpenAI's developer documentation for its web search tool does not name a search provider (OpenAI API docs).

You will find many articles saying ChatGPT "uses Bing" or "uses Google". OpenAI does not state either: the link to Microsoft's privacy statement is the closest it comes, and it does not say which provider is used for which question. What you can act on is the documented part: if OAI-SearchBot or OpenAI's searchbot IP addresses are blocked, ChatGPT search cannot show your website.

Where does Gemini get its information?

From Google Search. Google explains that grounding in the Gemini app means providing content from the Google Search index to the model when you ask a question (Google). Website owners can use the Google-Extended setting in robots.txt to control whether their content is used for Gemini training and grounding. Google states that this setting does not affect whether a site is included in Google Search or how it ranks there.

How do Google AI Overviews and AI Mode choose sources?

They are part of Google Search itself. Google says that to be shown as a supporting link in AI Overviews or AI Mode, a page must be indexed and eligible to appear in Google Search with a snippet, and that there are no extra technical requirements beyond that (Google Search Central). Both features may run several related searches across subtopics to build one answer.

Google's best-practice list for these features includes allowing crawling in robots.txt and by any CDN or hosting setup, keeping important content in text form, and keeping your Business Profile information up to date.

Does Microsoft Copilot use Bing?

Yes, and Microsoft documents it clearly. When web search is turned on, Copilot and Copilot Chat pick out the parts of a question where web information would help, turn them into a short search of a few words, send it to the Bing search service, and use what Bing returns to write the answer (Microsoft Learn). Copilot Chat even shows the exact searches it sent to Bing.

Microsoft's page covers Copilot and Copilot Chat as used with work accounts. For a business, the practical point is the same: if Bing does not have your website and business details, Copilot has little to work with.

Where does Perplexity get its answers?

Perplexity runs its own crawler, PerplexityBot, which it says is designed to surface and link websites in Perplexity's search results and is not used to collect training data for AI models (Perplexity). It also has Perplexity-User, which fetches a page when a user asks and generally ignores robots.txt. Perplexity's documentation does not say whether it also uses an outside search engine. Perplexity publishes the IP addresses of both, so a firewall can let them in reliably.

Does Claude search the web, and with what?

Claude can search the web when web search is turned on, and every answer comes with citations (Claude Help Center). Anthropic does not name a provider for its web results; its help page only says that images are chosen from web search results "powered by Bing".

Anthropic runs three visitors: ClaudeBot collects content that may be used for training, Claude-User fetches pages when a user asks, and Claude-SearchBot improves search results. Anthropic warns that blocking Claude-SearchBot may reduce your site's visibility and accuracy in user search results (Claude Help Center).

Where do Siri and Apple Intelligence get their answers?

Apple's crawler, Applebot, feeds the search technology built into Apple's products, and Apple says what it crawls can also give up-to-date context when AI models write answers, for example to general knowledge questions in Siri (Apple). A separate setting, Applebot-Extended, only controls whether that content may be used to train Apple's AI models; Apple says pages that block it can still appear in search results. Apple's page does not mention any outside search partner.

What this means for your business

There is no single place to be seen. In practice, a Luxembourg business needs to be readable by two big indexes and a handful of independent crawlers:

What to check	Which assistants it helps	Guide
robots.txt lets the search crawlers in (OAI-SearchBot, PerplexityBot, Claude-SearchBot, Applebot, Googlebot, Bingbot)	All of them	Let AI assistants read your website
Your firewall or Cloudflare does not block those same bots	All of them, especially ChatGPT, Perplexity and Claude	Check if Cloudflare or your firewall blocks AI bots
Your pages are indexed in both Google and Bing	Gemini, AI Overviews, AI Mode, Copilot	Get your site into Google and Bing
Google Business Profile is complete and current	Google AI Overviews, AI Mode, Gemini	Google Business Profile for Luxembourg businesses
Bing Places listing is claimed and correct	Copilot	Bing Places: the listing Copilot reads
Apple Business (formerly Business Connect) place card is correct	Siri, Apple Maps	Apple Business Connect: show up in Siri and Apple Maps

An example: Café Ribeiro, a fictional café in Luxembourg City, has a good Google Business Profile and ranks well on Google, so it can show up in AI Overviews. But its website sits behind a firewall rule that blocks unfamiliar bots, and it never added its site to Bing. Gemini and Google can find it; ChatGPT search, Perplexity and Copilot have much less to go on. Fixing the firewall rule and the Bing listing does not guarantee a mention, but it means every assistant can at least read the same correct facts.

Blocking AI training is a separate decision. Google, OpenAI, Anthropic, Perplexity and Apple all keep training and search apart, so you can refuse one and keep the other.

What the assistants say about you today

The quickest check is to ask the questions your customers ask. Start with Guide 01: Check what ChatGPT says about your business, or get a free report: we ask ChatGPT, Gemini and Google AI Overviews from Luxembourg, in English, French and German, and show you who they name and what they say about you.

FAQ

Does ChatGPT use Google or Bing?

OpenAI does not name a search engine. Its help page says ChatGPT search sometimes partners with other search providers and rewrites your question into targeted queries that it sends to them; for how those providers handle queries, it links to Microsoft's privacy statement and Shopify's privacy policy (OpenAI Help Center). It does not mention Google. OpenAI also runs its own crawler, OAI-SearchBot, to show websites in ChatGPT's search results (OpenAI).

Does Copilot use Bing?

Yes. Microsoft says that when web search is on, Copilot and Copilot Chat turn your question into a short search and send it to the Bing search service, then use what comes back to write the answer (Microsoft Learn).

Does Gemini use Google Search?

Yes. Google describes grounding in Gemini Apps as giving the model content from the Google Search index when you ask a question (Google).

If I block AI training bots, will I disappear from AI answers?

Not necessarily. Google, OpenAI, Anthropic, Perplexity and Apple each separate the crawler that feeds search answers from the one (or the setting) used for training, so you can say no to training and still be findable. Check each provider's crawler page before you change robots.txt.

Sources

Checked 24 October 2026. AI assistants change often; we re-check these sources when we update this page.