FrontendBackendFull-StackAround since 2020
Zod
Also written as Schema Validation, Runtime Validation
A library for checking at runtime that incoming data matches an expected shape — TypeScript types vanish when the code runs, so external data still needs verifying.
Think of it like
Checking the delivery against the order sheet, rather than trusting the label on the box.
Junior or senior?
A good sign someone understands that TypeScript types offer no protection against real API responses.
Senior sounds like
Validates at the boundary rather than everywhere.
Ask them
“Where in the stack did you validate, and why there rather than elsewhere?”