Validation in Spring Boot REST APIs | Spring Boot Interview Series #16

In this video, we will discuss **Validation in Spring Boot REST APIs**. This is Video #16 of our **Spring Boot Interview Series**. In the previous video, we discussed **ResponseEntity and HTTP Status Codes**. We understood how to return proper response body and status codes from REST APIs. Now, in this video, we will understand how to validate incoming request data before processing it. When a client sends data to our API, we should not directly trust that data. For example, the client may send blank title, negative price, missing fields, invalid email, or wrong input format. That is why validation is important. Topics covered in this video: 1. What is validation in Spring Boot REST APIs? 2. Why do we use validation? 3. How to validate request body using `@Valid` 4. Common validation annotations 5. Difference between `@NotNull` and `@NotBlank` 6. How validation works with `@RequestBody` 7. How to handle validation errors properly 8. Why validation errors should return `400 Bad Request` We will discuss important validation annotations like: `@Valid` `@NotNull` `@NotBlank` `@Size` `@Min` `@Max` `@Email` `@Pattern` We will also understand how Spring Boot throws `MethodArgumentNotValidException` when validation fails and how we can return field-level error messages to the client. For example, if the client sends: `title = blank` `price = negative` `email = invalid` Then the API should not process this data. Instead, it should return a proper validation error response with `400 Bad Request`. By the end of this video, you will be able to clearly explain `@Valid`, validation annotations, request body validation, and validation error handling in Spring Boot interviews. Watch the complete Spring Boot Interview Series playlist: [   • Spring Boot Interview Questions  ](   • Spring Boot Interview Questions  ) Connect with me on LinkedIn: [  / deep473  ](  / deep473  ) Subscribe to *Hosiyar.com* for more Java, Spring Boot, Backend Development, and Interview Preparation content. #SpringBoot #Validation #SpringBootInterviewQuestions #RestAPI #JavaInterview #JavaBackend #HosiyarDotCom