What is Cosmos DB?

Short answer: Azure Cosmos DB is a globally distributed, multi-model NoSQL database. Supports key-value, document, graph, and column-family data models. Provides automatic scaling, low latency, and global replication.

Real-world example (ShopNest)

ShopNest on Azure typically uses App Service + SQL Database + Blob Storage + Application Insights for monitoring.

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.