Validation of inputs to avoid security vulnerabilities (e.g. SQL?

Short answer: injection, XSS etc) Use parameterized queries / ORM to prevent SQL injection. Sanitize and encode user input to prevent XSS. Validate inputs rigorously on server side. Use built-in validation attributes and custom validators. Sample / Misc Interview Questions

Real-world example (ShopNest)

A ShopNest checkout request flows through middleware, hits a minimal API or controller, uses scoped services, and returns ProblemDetails on errors.

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.