Engine files

AI engines: where does each one pick its sources?

Every AI engine answers the same question from different sources. A brand visible in ChatGPT may never be mentioned in Perplexity. These files explain, engine by engine, how each reaches the web, which crawlers it uses and what actually works for visibility there.

Written by: Vextoo Geo Agency Team · Last updated:

✳ Short answer

Engines draw on two channels: training data and live web retrieval at answer time. On the retrieval side, ChatGPT uses its own OAI-SearchBot crawl plus search partners, Gemini and AI Overviews use Google’s index, Copilot uses Bing’s index, Perplexity its own PerplexityBot index, and Claude uses Claude-SearchBot. The common denominator: a site open to bots, readable without JavaScript, structured and consistent.

  1. E-01ChatGPTHow to appear in ChatGPT: how ChatGPT search picks sources, OAI-SearchBot vs GPTBot vs ChatGPT-User, 7 steps to get your brand recommended in ChatGPT, and how to measure it.MONITORED ENGINE
  2. E-02Gemini & AI OverviewsAppearing in Google AI Overviews, AI Mode and Gemini: how Google’s AI features pick sources, what Google-Extended does, snippet controls and practical optimization steps.MONITORED ENGINE
  3. E-03PerplexityBecoming a Perplexity source: PerplexityBot vs Perplexity-User, how Perplexity cites, freshness and sourcing signals, and steps to get your brand named in Perplexity answers.MONITORED ENGINE
  4. E-04Microsoft CopilotAppearing in Microsoft Copilot: how Copilot grounds web answers in Bing’s index, the Bing Webmaster Tools AI Performance report, IndexNow, and how to measure Copilot citations.MONITORED ENGINE
  5. E-05ClaudeAppearing in Claude: what Anthropic’s three crawlers ClaudeBot, Claude-SearchBot and Claude-User do, how to manage them in robots.txt, and how to become a source in Claude’s web search.MONITORED ENGINE
  6. E-06DeepSeekHow your brand gets named in DeepSeek: DeepSeek’s search mode, limited crawler documentation, representation in training data and why multilingual consistency matters. Practical steps and measurement.MONITORED ENGINE
  7. E-07GrokHow your brand gets named in Grok: Grok’s use of the web and X (Twitter) posts, X account consistency, the effect of real-time topics and what to watch out for.GUIDE COVERAGE
  8. E-08Meta AIHow your brand gets named in Meta AI: the meta-webindexer, meta-externalagent and meta-externalfetcher crawlers, Facebook/Instagram profile consistency and practical steps for Meta AI.GUIDE COVERAGE

Engine comparison table

EngineWeb sourceSearch/citation crawlerPractical priority
ChatGPTOpenAI search + search partnersOAI-SearchBotAllow OAI-SearchBot, Bing Webmaster, mentions in list articles
Gemini & AI OverviewsGoogle Search indexGooglebotClassic SEO + snippet-ready answer blocks
PerplexityIts own web indexPerplexityBotFresh, dated, sourced pages
CopilotBing indexBingbotBing Webmaster + IndexNow + AI Performance report
ClaudeWeb searchClaude-SearchBotAllow Claude-SearchBot, clear definition sentences
DeepSeekWeb search (search mode)No detailed public docsGeneral web authority, multilingual consistency
GrokWeb + X (Twitter) postsNo detailed public docsAn active, consistent brand account on X
Meta AIWeb search + Meta’s indexmeta-webindexerBot access, consistent Facebook/Instagram profiles

Five fundamentals that work in every engine

  1. Open door for bots: don’t block search/citation crawlers in robots.txt. Which bot does what: AI crawler guide.
  2. Readable without JavaScript: critical text must be in the HTML; most bots don’t run JS.
  3. Consistent entity: brand name, address and service definitions identical on every platform (entity SEO).
  4. Answer-first content: question as heading, answer in the first paragraph (citable content).
  5. Third-party mentions: engines often learn about brands from list articles, directories and news sites; a claim made only on your own site stays weak.

Frequently asked questions

01Do I need separate optimization for each AI engine?

The foundation is the same: bot access, readable and structured content, consistent entity data. The differences come from which index an engine relies on — Bing for Copilot, Google for AI Overviews, its own index for Perplexity. Measurement must be done per engine.

02Which AI engine matters most?

It depends on your audience. For general consumers ChatGPT and Google’s AI Overviews/Gemini surfaces lead; Perplexity and Claude matter for B2B and technical audiences, Copilot for Microsoft-centric enterprises. The audit also looks at which engines your audience actually uses.

Next step

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