Pathless Layouts and Route Groups

Quick Reference — TanStack Router

Pathless Layouts (Underscore Prefix)

Purpose: Wrap child routes with shared UI/logic without adding URL segment
Syntax: Prefix filename with _
routes/ ├── __root.tsx ├── _authenticated.tsx │ ├── _authenticated.index.tsx → / │ └── _authenticated.dashboard.tsx → /dashboard └── login.tsx

Route Groups (Parentheses Prefix)

Purpose: Organize files in folders without affecting URLs
Syntax: Wrap folder name in ( )
routes/ ├── (marketing)/ │ ├── (marketing).index.tsx → / │ └── (marketing).about.tsx → /about └── (app)/

When to Use What

Use Case Tool
Share header/sidebar across routes Pathless layout
Run auth checks before child loads Pathless layout
Organize many routes at same level Route group
Separate public/auth routes in file tree Route group