Kotlin Libraries That Will Save Your Project in 2024

Why Kotlin is Not Just "Another JVM Language"?

When JetBrains released Kotlin in 2016, few could have predicted that within a few years this language would become the standard for Android development and a top contender for the backend throne. Today, Kotlin is not just syntactic sugar over Java. It is a powerful ecosystem where each library solves a specific task elegantly and with minimal boilerplate.

In this article, we will break down the most popular Kotlin libraries that truly simplify a developer's life. We won't list everything — only what is worth learning right now. Let's go!

1. Ktor — Your New HTTP Client and Server

If you are looking for a lightweight, asynchronous, and fully configurable HTTP client (or even server) — Ktor will become your best friend. Unlike the heavyweight Spring Boot, Ktor does not impose an architecture. You decide which modules to include.

Example: HTTP client for fetching data

import io.ktor.client.*import io.ktor.client.engine.cio.*import io.ktor.client.request.*import io.ktor.client.statement.*

suspend fun main() {    val client = HttpClient(CIO)    val response: HttpResponse = client.get("https://api.github.com/repos/jetbrains/kotlin")    println("Status: ${response.status}")    println("Body: ${response.bodyAsText()}")    client.close()}

Ktor supports plugins for serialization, compression, logging, and authentication. It is one of the most popular Kotlin libraries for network operations.

2. Kotlinx.serialization — Painless Serialization

Forget about Gson and Jackson. Kotlinx.serialization works at the compiler level, not through reflection. This provides a performance boost and full type safety.

Example: Serializing a data class to JSON

import kotlinx.serialization.*import kotlinx.serialization.json.*

@Serializabledata class User(val name: String, val age: Int)

fun main() {    val user = User("Anna", 28)    val jsonString = Json.encodeToString(user)    println(jsonString) // {"name":"Anna","age":28}

    val decoded = Json.decodeFromString<User>(jsonString)    println(decoded) // User(name=Anna, age=28)}

The library supports polymorphism, custom serializers, and works with JSON, XML, CBOR, and even YAML. It is a must-have for any Kotlin project.

3. Koin — Dependency Injection Without Magic

Dagger? Hilt? Heavy, lots of code. Koin offers a simple DSL for DI, written in pure Kotlin. No code generation, no annotations — just functions.

Example: Simple module and injection

import org.koin.core.context.startKoinimport org.koin.dsl.moduleimport org.koin.core.component.KoinComponentimport org.koin.core.component.inject

class Repositoryclass Service(private val repo: Repository) {    fun doWork() = "Working with ${repo}"}

val myModule = module {    single { Repository() }    factory { Service(get()) }}

fun main() {    startKoin { modules(myModule) }    val service: Service = object : KoinComponent {}.inject()    println(service.doWork())}

Koin is ideal for medium and small projects where you don't want to pay the price of complexity.

4. Exposed — ORM for Those Who Don't Like ORMs

Most ORMs hide SQL, but Exposed works differently: it stays close to SQL but provides a convenient Kotlin DSL. You write in Kotlin and get clean SQL with autocompletion.

Example: Creating a table and querying

import org.jetbrains.exposed.sql.*import org.jetbrains.exposed.sql.transactions.transaction

object Users : Table() {    val id = integer("id").autoIncrement()    val name = varchar("name", 50)\