Tailwind CSS vs. StyleX: A real migration with 20 components

A hands-on migration of 20 production-style components from Tailwind CSS to StyleX using the newer sx={} prop syntax, with real measurements across lines of code, CSS output size, and build times. StyleX doubled the styling code (1,568 to 3,143 LOC) while producing nearly identical CSS bundle size (~20KB) and similar build times. The key differentiator was type safety: StyleX caught misspelled tokens, invalid variant keys, and broken conditional style arrays at compile time. Tailwind wins on speed, ecosystem (shadcn/ui, Headless UI, etc.), and prototyping velocity. StyleX wins on correctness, typed design tokens, and predictable style composition for large shared component libraries. The post also covers concrete migration pitfalls: barrel exports breaking the Babel plugin's static analysis, keyframes requiring a dedicated API, computed style key TypeScript errors, and conditional sx array patterns.