OpenAI — Foundation Models Platform

OpenAI is the creator of ChatGPT and the GPT series of large language models, having pioneered the commercial LLM API market. Founded in December 2015 by Sam Altman, Elon Musk, Greg Brockman, Ilya Sutskever, and others as a non-profit, it transitioned to a capped-profit model in 2019 and is currently restructuring as a for-profit public benefit corporation.

OpenAI's API platform provides access to text generation (GPT-4o, GPT-5, o-series reasoning models), image generation (DALL-E), speech-to-text (Whisper), text-to-speech, and embedding models. The platform supports fine-tuning, function calling, and the Responses API for agent-native workflows. The open-source Agents SDK and tools like code interpreter and web search enable developers to build sophisticated AI applications.

In February 2026, OpenAI closed a record $110 billion funding round from Amazon, Nvidia, and SoftBank, valuing the company at $840 billion post-money. The company employs approximately 3,500-7,200 people and is reportedly targeting a 2027 IPO at up to a $1 trillion valuation.