Using Kotlin with Spring Boot - A Beginner's Guide

Kotlin is a powerful language for building web applications, and when combined with the Spring Boot framework, it provides a robust platform for creating Java-based applications. In this guide, we'll walk you through the steps to use Kotlin with Spring Boot.

Setting Up Your Environment

Before you start, make sure you have Kotlin and a Java Development Kit (JDK) installed on your system. You can also use an integrated development environment (IDE) like IntelliJ IDEA for a smoother development experience.

Creating a Kotlin Spring Boot Application

Let's create a simple Spring Boot application in Kotlin that serves a "Hello, Kotlin with Spring Boot!" message when accessed.

1. Create a new Kotlin project in your IDE or use Spring Initializer to generate a new Spring Boot project with Kotlin as the language of choice.

2. In your project, navigate to the `src/main/kotlin` directory and create a Kotlin file, for example, `HelloKotlinController.kt`:

import org.springframework.web.bind.annotation.GetMapping
import org.springframework.web.bind.annotation.RestController
class HelloKotlinController {
fun hello(): String {
return "Hello, Kotlin with Spring Boot!"

In this code, we create a simple controller that responds with the "Hello, Kotlin with Spring Boot!" message when accessed at the root URL.

3. Run your Spring Boot application. You can do this from your IDE or by using the command line:

./gradlew bootRun

Your Spring Boot application should be running at `http://localhost:8080`. Access it in your web browser or use a tool like `curl` to see the "Hello, Kotlin with Spring Boot!" message.


Using Kotlin with Spring Boot is a great choice for building robust and scalable web applications. This example demonstrates how to set up a basic Spring Boot application with Kotlin, but you can extend it to create more complex web services, add database access, and implement authentication.

Happy coding with Kotlin and Spring Boot!