Over the years I have seen several approaches for validating inputs (@RequestParam, @RequestBody, etc.) for REST endpoints. Many of these approaches are pretty manual and require explicitly calling a validation mechanism. But is there a way to automate this process while writing as little code as possible, still validating all inputs, and responding with friendly messages to consumers? In this Snippet, I will present a minimalistic approach for handling this issue by using javax.validation.constraints combined with Spring MVC @RestController, @ControllerAdvice, and @ExceptionHandler.