LLM visibility is a broad term used by digital marketers and SEO practitioners to describe the degree to which a brand, product, domain, or piece of content is represented, cited, or recommended within the outputs of large language models and AI search systems. Just as organic search visibility measures how often a site appears in traditional search results, LLM visibility attempts to capture a brand’s presence across AI-mediated touchpoints such as ChatGPT, Perplexity, Google AI Overviews, Bing Copilot, and Claude. It is typically measured by submitting a set of representative prompts to AI systems and auditing whether the brand is mentioned, how it is described, and whether it is recommended over competitors. Unlike traditional SERP rank, LLM visibility is non-deterministic—models may produce different outputs for the same prompt—making measurement more complex. Specialist tools designed to track LLM visibility and citation share began emerging in 2024, and the metric is increasingly featured in SEO agency reporting and brand-monitoring dashboards.