ChatGPT

ChatGPT is a generative artificial intelligence chatbot developed by OpenAI and released in November 2022. It answers questions and performs tasks — writing, coding, translation, analysis and image generation — in conversational form, using OpenAI's GPT family of large language models. ChatGPT's launch accelerated the global "AI boom" and made it one of the fastest-adopted software products in history, reaching an estimated 100 million monthly active users within two months and about 900 million weekly active users by February 2026.^[1][2]

History

OpenAI, founded in 2015, developed the GPT series of language models and released GPT-3 in 2020. ChatGPT began as an experiment in applying reinforcement learning from human feedback to make those models more useful in conversation, and was released as a "research preview" on 30 November 2022, free to use.^[1]

Adoption exceeded expectations: within five days the service had a million users, and by January 2023 it reached an estimated 100 million monthly active users. OpenAI introduced a paid subscription tier in February 2023, added the more capable GPT-4 model in March 2023, and later that year added image generation, voice conversations and web browsing.^[1][3]

Development continued rapidly. The multimodal GPT-4o arrived in May 2024; reasoning models designed to "think" before answering followed from late 2024; and GPT-5 shipped in August 2025. In 2026, OpenAI released GPT-5.4 in March and the GPT-6 Astra generation in September 2026, which the company describes as its most intelligent and aligned model, with state-of-the-art results in computer use, coding and professional tasks.^[4][5]

Capabilities and technology

ChatGPT is built on large language models — neural networks trained on very large text corpora to predict and generate language. Early versions used supervised fine-tuning and reinforcement learning from human feedback (RLHF) to align responses with user intent; later systems added tool use, memory and extended reasoning at inference time.^[1]

The product spans text, speech and images, and works across web, desktop and mobile apps. Features include customised instructions, memory, file and data analysis, web search, image generation and "agent" modes that carry out multi-step tasks such as research or booking. OpenAI sells access through free, Plus, Pro, Business and Enterprise tiers.^[4]

Known limitations persist: models can produce plausible but incorrect statements ("hallucinations"), reflect biases present in training data, and be misused for academic dishonesty, misinformation or malware. Copyright disputes over training data, and debates over the future of creative and knowledge work, have accompanied the product throughout its history.^[1]

Applications and impact

ChatGPT is used for drafting and editing text, programming assistance, tutoring, customer service, translation and research — across households, schools, businesses and governments. Its success reshaped the technology industry, triggering heavy investment in AI data centres and a wave of competing assistants, including Google's Gemini, Anthropic's Claude, xAI's Grok and China's DeepSeek.^[1][2]

>See Also

• Chatbot
• Large Language Models
• GPT-5
• OpenAI
• Generative AI
• Hallucination