River AI raises $1.1 billion to develop personalized AI agents

River AI, a startup founded by former xAI co-founder Igor Babuschkin, has raised $1.1 billion in a funding round led by General Catalyst and AMP PBC. The investment includes strategic participation from Nvidia and AMD Ventures, alongside Y Combinator and Temasek.

Based in Palo Alto, the company aims to rebuild the AI stack to support personal, user-controlled AI agents. Rather than relying on centralized models from large laboratories, River AI focuses on open-weight models that users and enterprises can customize using their own data.

The company’s flagship product, the River API, utilizes low-rank adaptation (LoRA) and reinforcement learning to allow developers to fine-tune large language models in 15 to 20 minutes. The service is designed to be two to four times more cost-effective than closed-source alternatives and automates much of the underlying infrastructure management. Babuschkin’s long-term vision includes developing new hardware to enable personal AI to run locally, ensuring data privacy and user ownership.