OpenAI

The AI lab behind ChatGPT, GPT-4, and the o-series reasoning models — founded in 2015, now the most prominent commercial AI company.

OpenAI is the San Francisco AI lab that started the modern LLM era. Founded in 2015 by Sam Altman, Elon Musk, Ilya Sutskever, and others as a non-profit, restructured to a capped-profit model in 2019, and tightly partnered with Microsoft (~$13B+ in cumulative investment as of 2024). It matters because OpenAI's launches define the AI calendar. GPT-3 (2020) made few-shot prompting mainstream. ChatGPT (Nov 2022) crossed 100M users in two months. GPT-4 (2023) raised the capability bar. The o-series (o1, o3) introduced test-time reasoning. Each release ships a new product category — coding assistants, image generation (DALL-E), voice assistants, agentic workflows. A few key products: ChatGPT (consumer chatbot), the OpenAI API (developer access to GPT, Whisper, embeddings, DALL-E), Custom GPTs (no-code GPT customization), the GPT Store, Sora (text-to-video), and Operator (agentic browsing). Leadership is high-profile and turbulent — Sam Altman was briefly fired and reinstated in November 2023, and several alignment researchers (including Sutskever) have left to compete (Safe Superintelligence) or join Anthropic. OpenAI's stated mission is "safe and beneficial AGI for all of humanity". Critics argue the move toward commercial scale undermines that. Related: Sam Altman, ChatGPT, GPT family, Anthropic, AGI.