Legacy Java/Kotlin Server SDK

Statsig wrote this SDK in Kotlin, but it exposes methods and overrides to Java based applications.

Setup the SDK

1. Install the SDK

   Statsig now publishes v1.X.X+ of the SDK only to Maven Central.

   To install the SDK, set the Maven Central repository in your build.gradle. You probably already have this for other dependencies.

   groovy

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   repositories {
       mavenCentral()
   }
   

   Then add the dependency:

   groovy

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   implementation 'com.statsig:serversdk:1.X.X' // replace with the most up to date version
   // For >v1.24.0 If you are not using streaming and want to reduce the package size you can:
   implementation 'com.statsig:serversdk:1.X.X' {
       exclude(group = "io.grpc", module = "*") 
   }
   

   You can find the versions in the github releases of the open source sdk repository, or from the maven central repository.

   Jitpack deprecation

   jitpack provides v0.X.X versions of the SDK, but Statsig won't publish newer versions to jitpack.

   If you update Statsig to be pulled from Maven Central instead of jitpack, you can remove maven { url 'https://jitpack.io' } if Statsig was the only library you got from jitpack and you previously relied on v0.X.X of the SDK.

2. Initialize the SDK

   After installation, initialize the SDK using a Server Secret Key from the Statsig console.

   Don't embed your Server Secret Key in client-side applications, or expose it in any external-facing documents. However, if you accidentally expose it, you can create a new one in the Statsig console.

   JavaKotlin

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   import com.statsig.sdk.Statsig;
   
   StatsigOptions options = new StatsigOptions();
   // Customize options as needed. For example:
   // options.initTimeoutMs = 9999;
   Future initFuture = Statsig.initializeAsync("server-secret-key", options);
   initFuture.get();
   

   initialize performs a network request. After initialize completes, virtually all SDK operations are synchronous (refer to Evaluating Feature Gates in the Statsig SDK). The SDK fetches updates from Statsig in the background, independently of API calls.

Working with the SDK

Checking a Feature Flag/Gate

StatsigUser user = new StatsigUser("user_id");
Boolean isFeatureOn = Statsig.checkGateSync(user, "use_new_feature");

if (isFeatureOn) {
  // Gate is on, use new feature
} else {
  // Gate is off
}

Reading a Dynamic Config

DynamicConfig config = Statsig.getConfigSync(user, "awesome_product_details");
String itemName = config.getString("product_name", "Awesome Product v1");
double price = config.getDouble("price", 10.0);

Getting a Layer/Experiment

// Values via getLayer
Layer layer = Statsig.getLayerSync(user, "user_promo_experiments");
String title = layer.getString("title", "Welcome to Statsig!");
double discount = layer.getDouble("discount", 0.1);

// or, via getExperiment
DynamicConfig experiment = Statsig.getExperimentSync(user, "new_user_promo");
String expTitle = experiment.getString("title", "Welcome to Statsig!");
double expDiscount = experiment.getDouble("discount", 0.1);

Logging an Event

To track custom events and measure how features or experiment groups affect those events, call the Log Event API. Specify the user and event name to log, and optionally provide a value and metadata object:

Statsig.logEvent(user, "add_to_cart", "SKU_12345", 
    Map.of("price", "9.99", "item_name", "diet_coke_48_pack"));

Retrieving Feature Gate Metadata

When you need more than a boolean value from a gate evaluation, use the Get Feature Gate API, which returns a FeatureGate object with additional evaluation metadata:

FeatureGate gate = Statsig.getFeatureGateSync(user, "use_new_feature");
boolean value = gate.getValue();
String ruleId = gate.getRuleID();
EvaluationDetails details = gate.getEvaluationDetails();

Statsig User

In addition to userID, the top-level fields on StatsigUser are email, ip, userAgent, country, locale, and appVersion. You can also pass any key-value pairs in an object/dictionary to the custom field to create targeting based on them.

Typing on the StatsigUser object is lenient: you can pass numbers, strings, arrays, objects, and even enums or classes. However, evaluation operators only work on primitive types, mostly strings and numbers. The SDK attempts to cast custom field types to match the operator, but Statsig doesn't guarantee evaluation results for other types. For example, the SDK compares an array set as a custom field only as a string: there's no operator to match a value within that array.

Private Attributes

To keep sensitive user PII data out of logs, use the privateAttributes field on the StatsigUser object. This field accepts an object/dictionary of private user attributes. The SDK uses any attribute set in privateAttributes only for evaluation/targeting and removes it from all logs before Statsig sends them to its servers.

For example, if a feature gate should only pass for users with emails ending in "@statsig.com", but you don't want to log email addresses to Statsig, add the key-value pair { email: "my_user@statsig.com" } to privateAttributes on the user.

Shutdown

To gracefully shutdown the SDK and flush all events:

Statsig.shutdown();