Ktor

MediatorK works naturally with Ktor — register the mediator as a singleton in your DI module and inject it into your route configuration.

See Installation for dependency coordinates.

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Setup

Add the Ktor dependencies alongside MediatorK:

// build.gradle.kts
dependencies {
    implementation("io.ktor:ktor-server-core:3.1.3")
    implementation("io.ktor:ktor-server-netty:3.1.3")
    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.10.2")
}

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Routing

Pass the mediator into your route configuration function:

fun Application.configureRouting(mediator: Mediator) {
    routing {
        get("/users/{id}") {
            val user = mediator.send(GetUserQuery(call.parameters["id"]!!))
            call.respond(user)
        }

        post("/users") {
            val body = call.receive<CreateUserRequest>()
            val user = mediator.send(CreateUserCommand(body.name, body.email))
            call.respond(HttpStatusCode.Created, user)
        }
    }
}

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Wiring with Koin

Register the mediator as a singleton in your Koin module:

val appModule = module {
    single { AppRegistrar(get()) }
    single {
        MediatorFactory.create(
            registrars = listOf(get<AppRegistrar>()),
            pipelineBehaviors = listOf(LoggingBehavior()),
        )
    }
}

Install Koin and call your route configuration in Application:

fun Application.module() {
    install(Koin) { modules(appModule) }
    val mediator by inject<Mediator>()
    configureRouting(mediator)
}

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Sample — Prayer Times API

The /samples/sample-ktor module is a runnable Ktor server that fetches prayer times and Islamic calendar months from the Aladhan API. It mirrors the Android sample structure in three layers:

Layer	Routes	Pattern
Before	/before/prayer-times/{city} · /before/islamic-months	Route → UseCase → Repository → DataSource
After	/after/prayer-times/{city} · /after/islamic-months	Route → Mediator → Handler
After Super	/aftersuper/prayer-times/{city} · /aftersuper/islamic-months	After + all pipeline behaviors

# Run (from the repo root)
./gradlew :samples:sample-ktor:run

# Try it
curl http://localhost:8080/before/prayer-times/London
curl http://localhost:8080/after/prayer-times/London
curl http://localhost:8080/aftersuper/prayer-times/London

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Next

→ Kotlin Multiplatform