Explore the evolution of specs-rs in this 20-minute conference talk from the Rust KW Meetup. Delve into the user-facing API of specs-rs, examining how traits are utilized to construct a fast and seemingly simple interface. Learn about Entity Component Systems (ECS), storage types, component traits, system registration, system data, masks, and the BitAndSplit concept. Gain insights from speaker Coraline Sherratt's retrospective analysis of the specs-rs project, offering valuable lessons for Rust developers interested in API design and performance optimization.