Parallel Routes in Next.js App Router — Rendering Multiple Pages in One Layout

Parallel Routes let you render multiple pages simultaneously within the same layout. Instead of navigating away from a page to show another one, you can display both at the same time — a dashboard with independently navigable sections, a main content area alongside a sidebar that changes with its own navigation, or a feed with an openable detail panel that doesn't replace the feed. This is one of the more powerful App Router features and one of the more confusing to set up initially. Here's the complete pattern, including the design approach used for complex multi-panel interfaces like the generation tool at Pixova . The Core Concept — Named Slots Parallel routes use named slots: special folders prefixed with @ that define independent rendering areas within a layout. app/ ├── layout.tsx ← Receives slot props ├── page.tsx ← Default slot content ├── @sidebar/ │ ├── page.tsx ← Sidebar default │ └── settings/ │ └── page.tsx ← Sidebar settings view └── @modal/ ├── page.tsx ← Modal default (null) └── photo/[id]/ └── page.tsx ← Photo modal The layout receives each slot as a prop: // app/layout.tsx export default function Layout ({ children , sidebar , modal , }: { children : React . ReactNode ; sidebar : React . ReactNode ; modal : React . ReactNode ; }) { return ( < div className = "flex h-screen" > < aside className = "w-64 border-r" > { sidebar } </ aside > < main className = "flex-1" > { children } </ main > { modal } </ div > ); } Now children , sidebar , and modal can each navigate independently. Independent Navigation — The Key Behavior Each parallel route slot navigates independently. When a user navigates from / to /settings , the children slot updates. The sidebar slot stays exactly where it was — its navigation state is independent. This is the key difference from nested layouts. Nested layouts rerender from the changed segment outward. Parallel routes don't affect each other. User is at / (children shows home, sidebar shows default nav) User navigates to /setti