Explore cross-platform app development in Rust in this 44-minute conference talk from the Linux App Summit 2023. Dive into Fredrik Portström's findings from creating an experimental next-generation GUI framework. Learn about the architecture of a zero-weight framework, universal and timeless UI design principles, and functional GUI programming that departs from traditional object-oriented approaches. Discover how to generate apps from specifications using a universal non-plain text language for creating domain-specific languages. Examine safe high-performance extensibility techniques, including a compact machine-independent format for distributing programs and executing untrusted code safely. Gain insights into writing clear, maintainable, and high-performance code in Rust for cross-platform app development.