What is MongoDB and how is it different from SQL databases?

Short answer: MongoDB is a NoSQL document-oriented database that stores data in flexible, semi-structured documents rather than in rows and columns like SQL databases.

Explain a bit more

Unlike SQL databases, which rely on rigid schemas, MongoDB uses a schema-less approach where each document can have different fields and structures. Key differences: SQL Databases: Store data in tables with a fixed schema and use ACID transactions for consistency. MongoDB: Uses a document model (e.g., JSON-like structures) and offers more flexibility, scalability, and ease of replication but may sacrifice some consistency in distributed environments.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.