Which search engine does each AI use?
ChatGPT, Gemini, Perplexity, Claude and Copilot each read a different search index. What is confirmed, what is only reported, and what no one outside the companies knows.
Short answer. Each AI uses a different source. Gemini and Google's AI features use Google's index, Copilot sends queries to Bing, Perplexity runs its own index, and Claude's search is reported to use Brave. ChatGPT mixes several providers, and OpenAI has not said how much comes from Bing.
This matters because an AI with web search on only reads what its index has. If your page is not in that index, it cannot be quoted. It also depends on the route the AI takes: from memory, or from live search. Our guide on memory versus live search covers the difference. This page covers live search.
The summary table
| AI | Live search draws on | Status |
|---|---|---|
| ChatGPT | Several providers, plus OpenAI's own crawler | Partly confirmed, Bing's share undisclosed |
| Gemini, AI Overviews, AI Mode | Google Search's index | Confirmed |
| Perplexity | Its own index | Confirmed |
| Claude | Brave Search | Reported, not confirmed by Anthropic |
| Microsoft Copilot | Bing | Confirmed |
"Confirmed" means the company states it in its own documentation. "Reported" means credible reporting or analysis without a company statement.
ChatGPT: several providers, and Bing's share is not public
OpenAI said at launch that ChatGPT search "leverages third-party search providers, as well as content provided directly by our partners" (OpenAI, 31 Oct 2024; quoted by PYMNTS).
OpenAI's help article says ChatGPT search sometimes partners with other search providers and sends them rewritten queries (OpenAI help centre). Search Engine Land read that article as showing query and location data going to Microsoft (Search Engine Land).
Early tests pointed at Bing. In November 2024, Windows Latest found ChatGPT search results matched Bing's, with the same sites on the first or second Bing results pages (Windows Latest). That was one test, two years ago.
A September 2026 investigation by Peec AI, a company that sells AI-visibility tracking, argues the picture is now wider. It reports that ChatGPT's server events name its own index ("Labrador") and several external providers, that Bing appears mainly in Deep Research sessions, and that Google results also show up (Peec AI; provider list). Peec itself marks several of these as inference, and says the setup changes week to week.
What we can say plainly: OpenAI has confirmed it uses third-party search providers and has never published a share for Bing. Any article that says "ChatGPT uses Bing" as a flat fact goes further than OpenAI does.
What to do. Get indexed widely, in Google and Bing, and do not block OAI-SearchBot. OpenAI says sites that opt out of it will not appear in ChatGPT search answers (OpenAI).
Gemini and Google's AI features: Google's index
Google says the Google-Extended robots.txt token also governs grounding, "where Search index content is provided to models at prompt time", in the Gemini app and in Grounding with Google Search on Vertex AI (Google, updated 15 Oct 2026).
For AI Overviews and AI Mode, a page must be indexed and eligible to appear in Search with a snippet, and Google says there are "no additional requirements" (Google, updated 10 Dec 2025).
Google also says Google-Extended "does not impact a site's inclusion in Google Search". That page does not say whether it affects AI Overviews.
What to do. Rank in Google and use Search Console. Googlebot builds the Search index (Google).
Perplexity: its own index
Perplexity describes a search index "covering hundreds of billions of webpages", updated tens of thousands of times a second (Perplexity, 25 Sep 2025). That post introduces its Search API. Perplexity's crawler page says PerplexityBot surfaces and links websites in Perplexity search results (Perplexity docs).
We found no source that says whether Perplexity's answers also use any outside search provider.
What to do. Allow PerplexityBot in robots.txt and keep pages fast and clear.
Claude: reported to use Brave Search
On 21 March 2025 TechCrunch reported that Anthropic had added Brave Search to its subprocessor list, and that a test search in Claude returned citations identical to Brave's. Anthropic had not replied to TechCrunch when it published (TechCrunch).
A July 2026 analysis says Brave is still on the list, and that a second web-search provider, turbopuffer, a database for vector and full-text search, was added on 6 May 2026. Its role is not public (Xponent21). That analysis is secondary, and we could not read Anthropic's own list.
So: Brave is the best-supported answer, and Anthropic has not described its search setup in prose.
What to do. Make sure Brave can find your site. Brave says its index grows partly through an opt-in browsing programme called the Web Discovery Project (Brave). We could not confirm an official Brave submission form, so we do not recommend one. Anthropic also lists Claude-SearchBot as its search crawler (Anthropic). Do not block it.
Microsoft Copilot: Bing
Microsoft's documentation says Copilot "generates a search query that it sends to the Bing search service" when web search is on (Microsoft Learn, updated 18 Aug 2026).
What to do. Verify your site in Bing Webmaster Tools. IndexNow, which Bing, Naver, Seznam, Yandex and Yep support, lets you notify those engines when a page changes (IndexNow). It does not include Google. No first-party source ties IndexNow to ChatGPT.
The crawlers, by purpose
AI companies run separate crawlers for training, search and user requests. Blocking one does not block the others.
| AI | User-agent | Purpose |
|---|---|---|
| OpenAI | OAI-SearchBot | Search. Surfaces sites in ChatGPT search |
| OpenAI | GPTBot | May be used to train OpenAI's models |
| OpenAI | ChatGPT-User | Visits a page when a user's request needs it (OpenAI) |
Googlebot | Builds the Search index | |
Google-Extended | A robots.txt token for Gemini training and grounding, not a separate crawler (Google) | |
| Perplexity | PerplexityBot | Builds the search index |
| Perplexity | Perplexity-User | Fetches a page when a user's question needs it (Perplexity) |
| Anthropic | ClaudeBot | May be used for training |
| Anthropic | Claude-SearchBot | Search quality and indexing |
| Anthropic | Claude-User | Fetches a page when a Claude user asks (Anthropic) |
Microsoft's Bingbot also crawls for Bing, but we have not read Microsoft's current page on it, so we do not describe it further here.
What no one outside the companies knows
- How much of ChatGPT's search comes from Bing, from OpenAI's own index and from other providers.
- Whether Anthropic's search relies on Brave alone.
- Whether Perplexity uses outside sources alongside its own index.
- Whether
Google-Extendedhas any effect on AI Overviews.
We will update this page when any of these is confirmed. Want to see what each AI says about your business today? Our guide on how to check if AI recommends your business walks through it by hand, or aipozi can run it every morning.
Frequently asked questions
Does ChatGPT use Bing or Google? OpenAI says ChatGPT search uses third-party search providers and its own crawler, and its help article names Bing among the providers. OpenAI has not said how much comes from Bing, and an investigation by Peec AI in September 2026 argues the mix is broader, including Google results.
Which search engine does Claude use? Claude's web search is reported to use Brave Search. Anthropic lists Brave Search as a web-search subprocessor, but has not described the setup in its documentation, so treat it as strongly indicated rather than confirmed.
Does Gemini use Google Search? Yes. Google says content from the Search index is provided to its models at prompt time in the Gemini app, and that a page must be indexed and eligible for Search to appear in AI Overviews and AI Mode.
Does Perplexity use its own search engine? Yes. Perplexity runs its own index, built by its crawler PerplexityBot. Whether answers also draw on any outside source is not stated in the documentation we found.
Does the search engine matter for my business? Yes. A page the AI's search index has never seen cannot be read or cited when search is on. Check that your site is indexed in Google and Bing at least, and that the AI crawlers are allowed in robots.txt.