OpenAI

OpenAI develops the GPT family of large language models and the ChatGPT assistant, which is available through a web app, desktop and mobile clients. The same models are offered to developers through a REST API, alongside tooling for function calling, structured outputs, retrieval and image generation.

The company positions itself as a general-purpose AI platform: a consumer product for everyday users and an API for teams building their own applications. Paid consumer plans add higher usage limits and access to the most capable models, while API pricing is metered per token.