Backend

Routing is the core of any backend framework. It maps URLs to code that handles requests and sends responses. In this tutorial, you will learn how to define routes in Ktor, handle different HTTP methods, use path and query parameters, group routes, and handle errors properly. How Routing Works in Ktor Every Ktor route has three parts: HTTP method — GET, POST, PUT, DELETE, etc. Path — The URL pattern like /api/users/{id} Handler — The code that runs when a request matches routing { get("/hello") { // method + path call.respondText("Hi") // handler } } When a client sends GET /hello, Ktor finds the matching route and runs the handler. ...

In the previous tutorials, we learned what Ktor is and how it compares to Spring Boot. Now it is time to build a real project. We will set up a proper Ktor application with the right project structure, plugins, error handling, and configuration. This is the foundation for everything we build in this series. Project Structure Here is the project structure we will create: ktor-tutorial/ ├── build.gradle.kts ├── settings.gradle.kts ├── gradle.properties ├── src/ │ ├── main/ │ │ ├── kotlin/ │ │ │ └── com/kemalcodes/ │ │ │ ├── Application.kt │ │ │ └── plugins/ │ │ │ ├── Routing.kt │ │ │ └── StatusPages.kt │ │ └── resources/ │ │ └── logback.xml │ └── test/ │ └── kotlin/ │ └── com/kemalcodes/ │ └── ApplicationTest.kt This follows the standard Kotlin/Gradle layout. Source code goes in src/main/kotlin, resources in src/main/resources, and tests in src/test/kotlin. ...

You decided to build a backend with Kotlin. Good choice. But now you face another decision: Ktor or Spring Boot? Both are great frameworks. Both support Kotlin. But they are very different in philosophy, design, and use cases. Let’s compare them honestly. The Big Picture Ktor is a lightweight, modular framework built by JetBrains. It is Kotlin-native, coroutine-based, and you add features as plugins. Spring Boot is a full-featured, batteries-included framework from VMware (now Broadcom). It started as a Java framework and added Kotlin support later. ...

You know Kotlin. You build Android apps, maybe KMP apps. But what about the backend? Every app needs a server. An API to fetch data from. A backend to store users, handle payments, send notifications. You could learn Node.js and Express. Or Python and FastAPI. Or Java and Spring Boot. Or you could use the Kotlin you already know — and build your backend with Ktor. What is Ktor? Ktor is a backend framework built by JetBrains — the same company that created Kotlin. It lets you build web servers, REST APIs, microservices, and web applications using Kotlin. ...