Which AI platforms use GEO signals?
Direct answer
The major AI platforms that use GEO signals include ChatGPT (OpenAI), Google AI Overviews, Perplexity AI, Claude (Anthropic), and Gemini (Google). Each platform crawls, indexes, or retrieves web content and uses signals such as topical authority, content structure, schema markup, and source credibility to determine which pages to cite or summarize in generated responses. Use the SEORav AI Citation Checker to monitor your visibility across these platforms.
Key facts
- ChatGPT uses Bing index data and its own browsing capabilities to select citation sources
- Google AI Overviews synthesize answers from indexed web pages, favoring structured and authoritative content
- Perplexity AI cites every claim with inline source links, making it highly transparent for GEO tracking
- Claude and Gemini rely on training data and retrieval-augmented generation to surface relevant sources
The platforms in scope
Six surfaces matter for GEO in 2026: Google AI Overviews, ChatGPT (with browsing or SearchGPT), Perplexity, Microsoft Copilot, Claude (when given live web access), and Gemini. Voice assistants (Alexa, Siri, Google Assistant) read the same JSON-LD structured data, so the GEO work covers them without separate effort. Apple Intelligence joined this list in 2025 by reading Bing's index through ChatGPT.
How each platform retrieves sources
The differences matter when prioritising work. Google AI Overviews biases heavily towards pages already ranking in Google's top ten; if you are not ranking in classic search, you are not in the candidate set. ChatGPT and Copilot both use Bing's index, which means Bing Webmaster Tools is more important to GEO than most teams realise. Perplexity runs continuous crawls and an on-query fetch, so freshness hits Perplexity hardest. Claude does not browse by default. Gemini uses Google's index with its own ranking layer on top.
The citation patterns that emerged in 2025-2026
Industry studies through the period consistently find three things. Reddit is the most-cited domain across every major engine, sitting near 40% citation share. YouTube is the second-most-cited domain, appearing at roughly twice the share of the next-ranked domain. Wikipedia is the single largest source for ChatGPT specifically (close to 48% of its citations). The pattern says: GEO is not only about your own site. Where you appear on Reddit, YouTube, and (where relevant) Wikipedia moves the needle as much as on-site optimisation.
The signals each platform weighs most heavily
Google AI Overviews and Gemini lean on the same E-E-A-T factors classic Google search has been using for years (experience, expertise, authoritativeness, trust). ChatGPT/Copilot reward freshness and clear schema. Perplexity rewards original content and inline-citable claims heavily because its product depends on showing each citation against each sentence. Claude weighs schema less because the training data already encodes most of what schema would surface; for Claude, being on a domain it considers authoritative matters more than micro- optimisations.
A single audit that covers all of them
Run the target question through ChatGPT, Perplexity, Copilot, and Google search with AI Overviews enabled. Record which sources each cites. If you appear on Perplexity but not ChatGPT, the gap is likely schema or freshness. If you appear in Google AI Overviews but not Perplexity, the gap is original content or structural quality. That four-platform sweep is the cheapest way to see which signals your page is missing.