juniorSpring
What is a REST Controller in Spring?
Updated May 17, 2026
Short answer
@RestController is used to build REST APIs returning JSON responses.
Deep explanation
It combines @Controller and @ResponseBody. It automatically serializes return objects into JSON using Jackson.
Real-world example
Backend APIs for mobile apps.
Common mistakes
- Using @Controller instead of @RestController for APIs.
Follow-up questions
- What does @ResponseBody do?
- Which library handles JSON conversion?