DatabasesBackendTable-stakesAround since 2009
MongoDB
A popular NoSQL database that stores data as flexible, JSON-like documents rather than rows in tables.
Think of it like
Like keeping each customer's complete file, notes and all, in one single folder instead of splitting the same customer's info across ten filing cabinets.
Junior or senior?
Junior sounds like
Uses MongoDB like a SQL database with extra steps.
Senior sounds like
Can explain a schema decision specific to its document model — what they embedded versus referenced, and why.
Ask them
“How did you design your document schema — embedding related data, or referencing it across collections?”