CopilotKit is an open-source company building the interface layer between humans and AI agents. Its SDK and the open AG-UI protocol let developers embed agents directly inside apps - rendering interactive UI, sharing state, and supporting human-in-the-loop workflows - instead of bolting on a text-only chatbot. Founded in 2023 by brothers Atai and Uli Barkai and headquartered in the Seattle area, the company raised a $27M Series A in May 2026 and counts Google, Microsoft, Amazon, Oracle, and a large share of the Fortune 500 among adopters of its protocol.
Atai Barkai is the co-founder and CEO of CopilotKit, the Seattle-based open-source company building the interface layer between humans and AI agents. He and his brother Uli created AG-UI, an open protocol now adopted by Google, Microsoft, Amazon, Oracle, and major AI frameworks, with millions of weekly downloads. A physicist by training who pivoted into developer infrastructure at Meta and Doximity, Barkai bet early - during the GPT-3.5 era - that humans and agents would build software together, and is now turning that bet into the standard for how AI agents talk to the apps people actually use.