darkroomengineering/lenis

Lenis is a lightweight JavaScript library designed to provide fluid, momentum-based scrolling experiences for web interfaces. It functions as a frontend utility that decouples visual scroll position from the browser's native state, allowing for custom easing and duration while preserving standard browser accessibility, search functionality, and layout measurement tools.

The library distinguishes itself by normalizing input from mouse wheels and touch gestures into a unified stream, ensuring consistent physics across different devices. It operates by intercepting native scroll events and applying visual transformations to content containers, which allows for precise control over movement without altering the underlying document flow.

Beyond basic navigation, the tool supports the definition of vertical and horizontal movement constraints for both the entire viewport and specific page elements. It also provides integration hooks for external motion libraries, enabling the synchronization of scroll physics with complex, high-precision animations.