Perplexity AI, Inc., or simply Perplexity, is an American privately held software company offering a web search engine that processes user queries and synthesizes responses. It uses large language models and incorporates real-time web search capabilities, enabling it to provide responses based on current Internet content. With a conversational approach, Perplexity allows users to ask follow-up questions and receive contextual answers. All responses include citations to their sources from the Internet to support transparency and allow users to verify information. A free public version is available, while a paid Pro subscription offers access to more advanced language models and additional features.