Code Splitting

TanStack Router separates route code into critical (required to match and start loading) and non-critical (can be lazy-loaded). The bundler plugin can split automatically, or you can split manually with .lazy.tsx files.

CRITICAL: Never export component functions from route files — exported functions are included in the main bundle and bypass code splitting entirely.

CRITICAL: Use getRouteApi('/path') in code-split files, NOT import { Route } from './route'. Importing Route defeats code splitting.

What Stays in the Main Bundle (Critical)

• Path parsing/serialization
• validateSearch
• loader, beforeLoad
• Route context, static data
• Links, scripts, styles

What Gets Split (Non-Critical)