Next.js · App Router · Mid-Level · Architecture
What are parallel routes and intercepting routes used for?
Short Interview Answer
Parallel routes render multiple pages in one layout (slots); intercepting routes show another route in the current context (e.g. modal).
Detailed Explanation
Slots like `@modal` enable dashboards with independent loading states. Intercepting `(.)photo` opens a modal while keeping the underlying page, with deep links still working to the full page. These patterns power polished UX without losing URL semantics.