Kotlin Hackathon: How to Win and Not Burn Out

Kotlin at a Hackathon: Your Ticket to the Top Three

Hackathons are adrenaline, sleepless nights, tons of coffee, and the magic when raw code turns into a working prototype in 48 hours. But if you're still dragging Python or Java to a hackathon, you're missing a trump card. Kotlin is a language that gives you a superpower: write less, do more, and not go crazy from bugs in the early morning.

Why is Kotlin ideal for a hackathon? It's concise, null-safe, supports coroutines (asynchronous without pain) and works everywhere: from Android to backend on Ktor. In this article, I'll share real tips on how to prepare for a Kotlin hackathon and show project examples with code that you can adapt to your idea. Let's go!

Phase 1: Preparation — 80% of Success

A hackathon doesn't start when the theme is announced, but a week before. Here's what you need to do to avoid writing code from scratch.

1. Gather a "Gentleman's Kit" of Libraries

Don't waste time choosing tools. Determine your MVP stack in advance:

• Backend: Ktor (lightweight, fast, asynchronous) + Exposed (ORM for DB) + H2 or PostgreSQL.
• Frontend (if needed): Kotlin/JS or Compose Multiplatform — one language for all screens.
• Asynchrony: Kotlin Coroutines + Flow.
• Serialization: kotlinx.serialization — JSON without pain.
• Testing: Built-in kotlin.test — enough for quick checks.

2. Prepare a Project Template

Create a repository with a basic structure: Ktor setup, database connection, simple CRUD. This will save 2-3 hours on the first day of the hackathon. Example starter file Application.kt:

import io.ktor.server.engine.*import io.ktor.server.netty.*import io.ktor.server.routing.*import io.ktor.server.response.*import io.ktor.server.request.*import io.ktor.http.*

fun main() {    embeddedServer(Netty, port = 8080) {        routing {            get("/") {                call.respondText("Hello, Hackathon!", ContentType.Text.Plain)            }            get("/api/health") {                call.respond(mapOf("status" to "ok"))            }        }    }.start(wait = true)}

Phase 2: Choosing an Idea — Don't Overcomplicate

At a hackathon, the winners are not the most complex projects, but those that work and solve a specific pain point. Forget about neural networks and blockchain if you don't have a ready-made model. It's better to make a simple but complete product.

Example 1: Telegram Bot for Collecting Feedback in Kotlin

We use Kotlin + TelegramBots (library for bots). The bot collects anonymous feedback from employees and sends it to Google Sheets.

Key features: receiving messages, validation, writing to a table.

import org.telegram.telegrambots.bots.TelegramLongPollingBotimport org.telegram.telegrambots.meta.api.methods.send.SendMessageimport org.telegram.telegrambots.meta.api.objects.Update

class FeedbackBot(token: String) : TelegramLongPollingBot(token) {

    override fun onUpdateReceived(update: Update) {        val message = update.message.text        val chatId = update.message.chatId.toString()

        if (message.startsWith("/feedback")) {            val feedbackText = message.removePrefix("/feedback ").trim()            if (feedbackText.isNotEmpty()) {                // Save to DB or send to Google Sheets                saveFeedback(feedbackText)                sendMessage(chatId, "Thank you! Your feedback has been received.")            } else {                sendMessage(chatId, "Please write text after /feedback")