Integration · SDK
Kotlin
The Kotlin client ships on Maven Central as ai.metapolicy:sdk. JVM 11+ for backend, Android API 21+ for mobile. Coroutines-native; the suspend functions slot directly into your existing ViewModel scope or backend handler.
The contract
What flows in
- Decide requests as suspend functions returning Result
- Reward events emitted through a single suspend function call
- Network handled by OkHttp; you can supply your own client if your app already does
What flows out
- Assignment payload + propensity logged at the call site
- Errors typed: network, auth, schema validation
Setup
- 01Add ai.metapolicy:sdk to your build.gradle.kts dependencies
- 02Initialise the client in your Application onCreate / backend bootstrap with an environment-scoped key
- 03Call client.decide(experiment, userId, context) from any coroutine scope
- 04Emit rewards via client.reward(userId, experiment, rewardSpec, value)
- 05Optional: wire the Compose-friendly @Composable rememberDecision(...) helper for declarative paywall UIs
Android specifics
Decisions are cached in a process-local LRU keyed on (experiment, userId, contextHash). The cache is invalidated on app foregrounding by default, which keeps the propensity honest after long pauses.
Network calls go through OkHttp by default. If your app already runs OkHttp with custom interceptors (e.g. for tracing), you can supply that client instance at init time.
Other sdk integrations
PythonAsync client for FastAPI / Django / Celery. Same six-method surface as every other SDK.TypeScriptUniversal client. Same wire format whether you ship in Node, the browser, or React Native.Swiftasync/await client for iOS, macOS, watchOS, tvOS. Same wire format as the rest.FlutterDart 3 client for the Flutter mobile-growth stack. One client across iOS + Android.
Wire Kotlin in a 30-minute call.
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