ChatGPT is an artificial intelligence (AI) chatbot that uses natural language processing to create human-like conversational dialogue. It is built upon either GPT-3.5 or GPT-4, members of OpenAIs proprietary series of generative pre-trained transformer (GPT) models, based on the transformer architecture developed by Google. ChatGPT was released as a freely available research preview, but due to its popularity, OpenAI now operates the service on a freemium model. ChatGPT can be used for various tasks, including text generation, question answering, language translation, summarization, information retrieval, code writing and interpretation, natural language understanding, learning from feedback, conversation and engagement, assistance, and support. ChatGPT runs on a language model architecture created by OpenAI called the Generative Pre-trained Transformer (GPT). The specific GPT used by ChatGPT is fine-tuned from a model in the GPT-3.5 series, according to OpenAI. With a subscription to ChatGPT Plus, users can access ChatGPT with GPT-4, Open AIs most advanced model. ChatGPT has been used for various purposes, including composing emails, essays, and code, drafting music, summarizing articles, podcasts, or presentations, scripting social media posts, creating titles for articles, solving math problems, and more.