What is Express.js and why is it used in MERN?
PICTURE THIS: A REST CALL
Simple meaning
Express is a minimal Node framework for routing, middleware, and HTTP responses.
WHY — Express instead of guessing?
Why interviewers care about Express:
who only read docs from people who shipped.
and tied to Full Stack 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:
- 1Express is a minimal
Node framework for routing, middleware, and HTTP responses.
- 2It sits on Node's
http module and is the usual API layer in MERN.
- 3You use it to
define REST endpoints that the React client calls.
- 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
Express is a minimal Node framework for routing, middleware, and HTTP responses. It sits on Node's http module and is the usual API layer in MERN.