GEO Wiki is a bilingual encyclopedia platform that documents Generative Engine Optimization (GEO), the practice of making content discoverable and citable in AI-generated answers. The platform covers core concepts, practical methods, AI search engine profiles, and peer-reviewed research, with claims linked to original sources. GEO Wiki addresses optimization for generative AI systems such as ChatGPT, Perplexity, Google AI Overviews, and Gemini through content structure, source credibility, structured data, and crawler access management. The platform includes a wiki with definitions, a learn section, playbooks, research papers, engine profiles, and project repositories. The Pulse feature aggregates updates on AI search and GEO developments, refreshing every two hours with direct source links. Free tools include a Citability Checker, Schema Markup Checker, AI Crawler Access Checker, and llms.txt Generator.