Lars Grammel

Lars Grammel is a Member of Technical Staff at Vercel and a key builder behind Vercel's AI SDK. Before joining Vercel, he created ModelFusion, an open-source TypeScript library for building AI applications. Following Vercel's acquisition of ModelFusion in 2023, the library became the foundation for the next generation of the AI SDK. Lars led the SDK's development from 2023 through 2025 and, more recently, created a software factory for the AI SDK. Today, the toolkit receives more than 20 million monthly downloads and is used by organizations ranging from startups to Fortune 500 companies.