What is a layout in the App Router?
PICTURE THIS: HOW TO EXPLAIN IT
Simple meaning
A layout wraps child routes and does not remount on navigation inside that segment, so shared chrome stays mounted.
WHY — Next.js instead of guessing?
Why interviewers care about Next.js:
who only read docs from people who shipped.
and tied to Frontend work.
Name the idea, why it exists, then one short example.
End with when you use it and one common pitfall.
STEPS — What happens step by step?
Before you speak the answer, walk the interviewer through these steps:
- 1A layout wraps child
routes and does not remount on navigation inside that segment, so shared chrome stays mounted.
- 2Why it exists
Nested layouts compose for dashboards.
- 3I put providers that
must persist, like a sidebar state, in the right layout rather than every page.
- 4Give an example
One tiny concrete case you can say aloud.
- 5Common mistake
What juniors usually get wrong.
- 6Close
When you pick this over the alternative.
EXAMPLE — See it in action
Here's a short line you can speak, broken into clear beats:
Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.
Key takeaway
A layout wraps child routes and does not remount on navigation inside that segment, so shared chrome stays mounted. Nested layouts compose for dashboards.