OpenAI

OpenAI is the AI research organization and API platform that produced GPT-3, ChatGPT, GPT-4, o1, Whisper, DALL·E, and the text-embedding-3 models — making it the most widely integrated AI API in the developer ecosystem. The OpenAI API provides access to frontier language models for text generation, reasoning, function calling, vision analysis, speech-to-text transcription, image generation, and text embeddings. GPT-4o (Omni) is OpenAI's flagship multimodal model supporting text, image, audio, and vision inputs with native function calling and a 128K context window. The o1 series introduces a chain-of-thought reasoning model that trades response speed for significantly improved performance on complex math, science, and coding problems. OpenAI's Function Calling feature allows models to invoke external tools (APIs, databases, calculators) in a structured way, making it the standard architecture for building tool-augmented AI agents. The Assistants API provides stateful conversation management, file retrieval, and code interpreter execution as a managed service without custom session handling.