Spring Boot Validation Groups

If you've ever written nearly-identical CreateRequest and UpdateRequest DTOs just because the validation rules differ (ID must be null on create, required on update), there's a better way. Spring Boot's Validation Groups let you define different constraint profiles on a single DTO and activate the right one per endpoint. The setup: public interface OnCreate {} public interface OnUpdate {} public class UserRequest { @Null(groups = OnCreate.class) @NotNull(groups = OnUpdate.class) private Long id; @NotBlank private String name; } In your controller, swap @valid for @Validated with the group: @PostMapping public ResponseEntity<?> create(@Validated(OnCreate.class) @RequestBody UserRequest req) { ... } @PutMapping("/{id}") public ResponseEntity<?> update(@Validated(OnUpdate.class) @RequestBody UserRequest req) { ... } Spring applies only the constraints matching the group you specify. Constraints with no group annotation apply in both cases. This scales well for lifecycle-based