Kotlin Quickstart

The Repost build plugin turns your .repost schema into an idiomatic Kotlin client: immutable models with a builder DSL, a webhooks.<catalog>.<member>() tree, suspend sends that respect structured concurrency, and a shared runtime that handles retries, idempotency, and delivery reconciliation. It sits on the same framework-neutral runtime as the Java SDK and the TypeScript, Go, and Python SDKs, pinned by a cross-language conformance suite. The runtime is published to Maven Central under the sh.repost group and is server-side only — it holds a publish credential and must not ship in an Android app or any untrusted client.

The published runtime is version 1.0.18, the Gradle plugin id sh.repost.sdk is 1.0.18 on the Gradle Plugin Portal, and the schema engine is 0.9.0 on Maven Central. Java projects should follow the Java quickstart instead.

Apply the plugin and BOM

Apply the sh.repost.sdk plugin, import repost-bom so every Repost artifact stays on one version, and depend on repost-client-kotlin. A complete working project lives in the repo under examples/kotlin.

build.gradle.kts

plugins {
    kotlin("jvm") version "2.1.21"
    id("sh.repost.sdk") version "1.0.18"
}

// A Kotlin-only project turns off the Java generator.
repostSdk.generators.named("javaSdk") { enabled.set(false) }

dependencies {
    implementation(platform("sh.repost:repost-bom:1.0.18"))
    implementation("sh.repost:repost-client-kotlin")
}

kotlin {
    compilerOptions {
        languageVersion.set(org.jetbrains.kotlin.gradle.dsl.KotlinVersion.KOTLIN_2_1)
        apiVersion.set(org.jetbrains.kotlin.gradle.dsl.KotlinVersion.KOTLIN_2_1)
    }
}

settings.gradle.kts

pluginManagement {
    repositories { gradlePluginPortal() }
}

dependencyResolutionManagement {
    repositories { mavenCentral() }
}

The plugin adds no transitive HTTP, JSON, or logging libraries — the transport is a source-verified, relocated Apache HttpClient baseline inside the runtime, so it cannot collide with your own dependencies. Only kotlinx-coroutines comes along, for the suspend API.

Define the schema

repost schema init --language kotlin --output ./src/main/kotlin scaffolds a repost/ directory. Declare your events and a Kotlin generator block:

repost/schema.repost

generator kotlinSdk {
  language       = "kotlin"
  output         = "../build/generated/sources/repost/kotlinSdk/kotlin"
  resourceOutput = "../build/generated/resources/repost/kotlinSdk"
  packageName    = "com.example.repost"
  clientName     = "RepostClient"
}

model Order {
  id String
}

type Order {
  created
}

event OrderCreated {
  type      @type(Order.created)
  data      Order
  timestamp DateTime
}

The generator block sets four things the other languages don’t need — Code generation explains each field, the engine pinning, and multi-module builds.

Generate the client

The plugin binds repostGenerate before compileKotlin, so a normal build already has your client. To run generation on its own:

./gradlew repostGenerate

Your first send

RepostClient is AutoCloseable, so use { } scopes it; the no-arg constructor reads the credential and endpoint from the environment. main here is a suspend fun. Build a model inline with the DSL, or pass a prebuilt one:

val result = repost.webhooks.order.created(customerId = "customer-123") {
    id = "order-123"
}
println(result.id)

val prebuilt = Order { id = "order-456" }
println(repost.webhooks.order.created("customer-123", prebuilt).id)

A successful send returns a SendResult whose deliveryState is ACCEPTED; any failure throws a RepostException subclass — Reliability covers the full outcome model. close() (via use) returns every owned thread and connection to baseline.

Continue

Code generation

The generator block, the repostGenerateCheck CI gate, and multi-module builds.

Configuration

Credentials, timeouts, retries, and the trailing-lambda config DSL.

Reliability

Idempotency, the five delivery states, and coroutine cancellation.

Send

Schema

Publishing

Delivery

Customer experience

TypeScript

Go

C#

Python

Java

Kotlin

Kotlin Quickstart

Your first send

Continue

Code generation

Configuration

Reliability

​Your first send

​Continue

Code generation

Configuration

Reliability

Your first send

Continue