TaskMatrix.AI is a novel AI ecosystem that aims to connect foundation models with millions of APIs to enable effective task completion. By leveraging specialized models and systems alongside foundation models, TaskMatrix.AI can address domain-specific tasks more efficiently. This paper presents the vision for building this ecosystem, explaining the key components and showcasing its feasibility and challenges through case studies. The development of TaskMatrix.AI could significantly transform AI capabilities and how tasks are completed in both digital and physical domains.