Bonsplit is a new library for adding native macOS tabs and splits to apps. It offers out-of-the-box 120fps animations, drag-and-drop reordering, and full SwiftUI support. Developers can integrate it via Swift Package Manager to manage panes, tabs, and focus programmatically with a clean API.

The library addresses a common gap for macOS developers building complex, document-based applications. While Apple provides basic tab controls, Bonsplit offers a more flexible, performant system for managing multiple split panes and tab states. It handles animations, dirty indicators, and keyboard navigation natively.

Key features include configurable BonsplitController and BonsplitDelegate protocols for event handling. Developers can control tab lifecycle, pane splitting orientation, and appearance metrics like tab bar height. The library aims to reduce boilerplate for building IDE-like interfaces or multi-document editors on macOS.