Kotlin SDK - Installation

Requirements

Requirement	Minimum
JVM	17 (tested on 17, 21 and 25)
Kotlin	2.0 or newer on the consumer side - the SDK is compiled with 2.4.10 and targets JVM 17 bytecode
Gradle	8.x or 9.x (Kotlin DSL recommended)
Ktor client engine	one, of your choosing - see Choosing an engine

Artifacts

Artifact	What it is	When you need it
`dev.westyx.nexus:nexus-kotlin-sdk`	the client	always
`dev.westyx.nexus:nexus-kotlin-openfeature`	OpenFeature provider	to evaluate flags through the OpenFeature API
`dev.westyx.nexus:nexus-ktor-plugin`	Ktor server plugin	to tie the client to a Ktor application’s lifecycle

Each is versioned and released together, so use the same version for all of them.

Choosing an engine

The SDK depends on ktor-client-core and bundles no HTTP engine. Engine choice is an application-level decision - connection pooling, TLS, proxy handling and HTTP/2 all live there - and a bundled engine would sit alongside whichever one the application already uses. Add exactly one:

implementation("io.ktor:ktor-client-cio:3.5.1")      // pure-Kotlin, no extra native deps
// implementation("io.ktor:ktor-client-okhttp:3.5.1") // if you already use OkHttp
// implementation("io.ktor:ktor-client-java:3.5.1")   // the JDK HttpClient
// implementation("io.ktor:ktor-client-apache5:3.5.1")

…or pass an engine explicitly, which is also how you share the application’s own engine configuration:

import io.ktor.client.engine.okhttp.OkHttp

val client = NexusClient.create(config, engine = OkHttp.create { /* proxy, TLS, pool */ })

If no engine is available, NexusClient.create raises NexusNoHttpEngineException, whose message names the exact dependency line to add.

A Ktor server dependency does not bring a Ktor client engine with it. Applications using the Ktor plugin still need one of the lines above.

GitLab package registry

The artifacts are hosted on the GitLab Maven Package Registry. It is public - no token is required to install.

Gradle (Kotlin DSL)

// settings.gradle.kts
dependencyResolutionManagement {
    repositories {
        mavenCentral()
        maven {
            url = uri("https://gitlab.com/api/v4/projects/82635144/packages/maven")
        }
    }
}

// build.gradle.kts
dependencies {
    implementation("dev.westyx.nexus:nexus-kotlin-sdk:0.15.1")
    implementation("io.ktor:ktor-client-cio:3.5.1")
}

Gradle (Groovy DSL)

// build.gradle
repositories {
    mavenCentral()
    maven {
        url "https://gitlab.com/api/v4/projects/82635144/packages/maven"
    }
}

dependencies {
    implementation "dev.westyx.nexus:nexus-kotlin-sdk:0.15.1"
    implementation "io.ktor:ktor-client-cio:3.5.1"
}

Maven

<!-- pom.xml -->
<repositories>
  <repository>
    <id>westyx-nexus-sdk</id>
    <url>https://gitlab.com/api/v4/projects/82635144/packages/maven</url>
  </repository>
</repositories>

<!-- pom.xml dependencies -->
<dependency>
  <groupId>dev.westyx.nexus</groupId>
  <artifactId>nexus-kotlin-sdk</artifactId>
  <version>0.15.1</version>
</dependency>
<dependency>
  <groupId>io.ktor</groupId>
  <artifactId>ktor-client-cio-jvm</artifactId>
  <version>3.5.1</version>
</dependency>

Transitive dependencies

What the SDK brings with it, and why. Four are api dependencies - their types appear in the SDK’s own signatures, so you can compile against them:

Artifact	Version	Scope	Appears in
`io.ktor:ktor-client-core`	3.5.1	api	`HttpClientEngine`, the `create` parameter
`org.jetbrains.kotlinx:kotlinx-coroutines-core`	1.11.0	api	`StateFlow`, `NexusClient.streamStatus`
`org.jetbrains.kotlinx:kotlinx-serialization-json`	1.11.0	api	`JsonElement`, `NexusClient.getJson`
`org.slf4j:slf4j-api`	2.0.18	api	`Logger`, `NexusConfig.logger`
`io.ktor:ktor-client-content-negotiation`	3.5.1	runtime	internal
`io.ktor:ktor-serialization-kotlinx-json`	3.5.1	runtime	internal

No HTTP engine and no AWS SDK are declared - the engine is yours to pick, and the AWS SDK is needed only by the aws_iam WIF provider (see Workload identity). A CI job asserts both against the published POM on every pipeline.

Overview

Backend SDKs

Browser SDKs

OpenFeature Providers

Kotlin SDK - Installation

Requirements

Artifacts

Choosing an engine

GitLab package registry

Gradle (Kotlin DSL)

Gradle (Groovy DSL)

Maven

Transitive dependencies

​Requirements

​Artifacts

​Choosing an engine

​GitLab package registry

​Gradle (Kotlin DSL)

​Gradle (Groovy DSL)

​Maven

​Transitive dependencies

Requirements

Artifacts

Choosing an engine

GitLab package registry

Gradle (Kotlin DSL)

Gradle (Groovy DSL)

Maven

Transitive dependencies