Kotlin Multiplatform Experiments installation

1
Install the dependency
Required
Add the PostHog KMP SDK to your shared module's commonMain source set:
shared/build.gradle.kts
kotlin { sourceSets { commonMain.dependencies { implementation("com.posthog:posthog-kmp:0.+") } } }
0.+ resolves to the latest 0.x release. The SDK is a pre-release, so the API can change between minor versions – pin an exact version from Maven Central if you would rather upgrade deliberately. Kotlin/Wasm support requires 0.2.0 or higher.

Configure PostHog

Required

Call PostHog.setup() once, early in your app's lifecycle. The config is shared across every target – only the PostHogContext differs per platform.

Android needs the Application instance, so set PostHog up from your Application class – not from an Activity, whose onCreate re-runs on every recreation (for example, on rotation):

MyApplication.kt
import android.app.Application
import com.posthog.kmp.PostHog
import com.posthog.kmp.PostHogConfig
import com.posthog.kmp.PostHogContext

class MyApplication : Application() {
    override fun onCreate() {
        super.onCreate()

        PostHog.setup(
            config = PostHogConfig(
                apiKey = "<ph_project_token>",
                host = "https://us.i.posthog.com",
            ),
            context = PostHogContext(this),
        )
    }
}

android/src/main/AndroidManifest.xml
<application android:name=".MyApplication" ...>

On iOS, use the no-argument PostHogContext():

MainViewController.kt
import com.posthog.kmp.PostHog
import com.posthog.kmp.PostHogConfig
import com.posthog.kmp.PostHogContext

fun MainViewController() = ComposeUIViewController {
    LaunchedEffect(Unit) {
        PostHog.setup(
            config = PostHogConfig(
                apiKey = "<ph_project_token>",
                host = "https://us.i.posthog.com",
            ),
            context = PostHogContext(),
        )
    }
    App()
}

On the web (Kotlin/JS and Kotlin/Wasm), use the no-argument PostHogContext():

main.kt
import com.posthog.kmp.PostHog
import com.posthog.kmp.PostHogConfig
import com.posthog.kmp.PostHogContext

fun main() {
    PostHog.setup(
        config = PostHogConfig(
            apiKey = "<ph_project_token>",
            host = "https://us.i.posthog.com",
        ),
        context = PostHogContext(),
    )
}

On the JVM – for example, a Compose Multiplatform desktop app – use the no-argument PostHogContext():

main.kt
import com.posthog.kmp.PostHog
import com.posthog.kmp.PostHogConfig
import com.posthog.kmp.PostHogContext

fun main() = application {
    PostHog.setup(
        config = PostHogConfig(
            apiKey = "<ph_project_token>",
            host = "https://us.i.posthog.com",
        ),
        context = PostHogContext(),
    )
    // ...
}

Implement your experiment

Required

Experiments run on top of our feature flags. You can define which version of your code runs based on the return value of the feature flag:

if (PostHog.getFeatureFlag("your-experiment-feature-flag") == "test") {
    // do something
} else {
    // It's a good idea to let control variant always be the default behaviour,
    // so if something goes wrong with flag evaluation, you don't break your app.
}

4
Run your experiment
Required
Once you've implemented the feature flag in your code, you'll enable it for a target audience by creating a new experiment in the PostHog dashboard.

Next steps

Recommended

Now that you're running experiments, continue with the resources below to learn what else Experiments enables within the PostHog platform.

Resource	Description
Creating an experiment	How to create an experiment in PostHog
Adding experiment code	How to implement experiments for all platforms
Statistical significance	Understanding when results are meaningful
Experiment insights	How to analyze your experiment data
More tutorials	Other real-world examples and use cases

Kotlin Multiplatform Experiments installation

Install the dependency

Configure PostHog

Implement your experiment

Run your experiment

Next steps

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