Katha - Book Writing Platform
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Coding · Design
Word processors aren't designed for writing books — they're designed for documents. Katha is a cross-platform book editor built around a custom .bk plain-text file format, a Rust parser compiled to WebAssembly, and a fully custom text engine (no contenteditable) that flows text across fixed-height pages in a two-page spread layout. The parsing logic lives in a single Rust library shared across both the web app (React + Vite, deployed to Vercel) and the desktop app (Tauri), so there's one source of truth for the file format across platforms. Canvas API handles text measurement for pagination; IndexedDB stores file handles for the File System Access API.