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Setup the SDK

1

Install the SDK

The package is hosted on Nuget. You can either install it from your Visual Studio’s Nuget package manager, or through the NuGet CLI:
nuget install Statsig
2

Initialize the SDK

After installation, you will need to initialize the SDK using a Server Secret Key from the Statsig console.
Do NOT 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.
using Statsig; using Statsig.Server;  await StatsigServer.Initialize(  "server-secret-key",  // optionally customize the SDKs configuration via StatsigOptions  new StatsigOptions(  environment: new StatsigEnvironment(EnvironmentTier.Development)  ) );
initialize will perform a network request. After initialize completes, virtually all SDK operations will be synchronous (See Evaluating Feature Gates in the Statsig SDK). The SDK will fetch updates from Statsig in the background, independently of your API calls.

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Working with the SDK

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Checking a Feature Flag/Gate

Now that your SDK is initialized, let’s fetch a Feature Gate. Feature Gates can be used to create logic branches in code that can be rolled out to different users from the Statsig Console. Gates are always CLOSED or OFF (think return false;) by default. From this point on, all APIs will require you to specify the user (see Statsig user) associated with the request. For example, check a gate for a certain user like this: 
var user = new StatsigUser { UserID = "some_user_id", Email = "user@email.com" }; var useNewFeature = await StatsigServer.CheckGate(user, "use_new_feature"); if (useNewFeature) {  // Gate is on, enable new feature } else {  // Gate is off }

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Reading a Dynamic Config

Feature Gates can be very useful for simple on/off switches, with optional but advanced user targeting. However, if you want to be able send a different set of values (strings, numbers, and etc.) to your clients based on specific user attributes, e.g. country, Dynamic Configs can help you with that. The API is very similar to Feature Gates, but you get an entire json object you can configure on the server and you can fetch typed parameters from it. 
var config = await StatsigServer.GetConfig(user, "awesome_product_details"); var itemName = config.Get<string>("product_name", "Awesome Product v1"); var price = config.Get<double>("price", 10.0);

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Getting a Layer/Experiment

Then we have Layers/Experiments, which you can use to run A/B/n experiments. We offer two APIs, but we recommend the use of layers to enable quicker iterations with parameter reuse. 
// Values via GetLayer var layer = await StatsigServer.GetLayer(user, "user_promo_experiments"); var title = layer.Get<string>("title", "Welcome to Statsig!"); var discount = layer.Get<double>("discount", 0.1);  // or, via GetExperiment var experiment = await StatsigServer.GetExperiment(user, "new_user_promo"); var expTitle = experiment.Get<string>("title", "Welcome to Statsig!"); var expDiscount = experiment.Get<double>("discount", 0.1);  var price = msrp * (1 - discount);

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Logging an Event

Now that you have a Feature Gate or an Experiment set up, you may want to track some custom events and see how your new features or different experiment groups affect these events. This is super easy with Statsig - simply call the Log Event API and specify the user and event name to log; you additionally provide some value and/or an object of metadata to be logged together with the event: 
StatsigServer.LogEvent(user, "add_to_cart", "SKU_12345",   new Dictionary<string, string> {  { "price", "9.99" },  { "item_name", "diet_coke_48_pack" }  });
Learn more about identifying users, group analytics, and best practices for logging events in the logging events guide.

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Statsig User

When calling APIs that require a user, you should pass as much information as possible in order to take advantage of advanced gate and config conditions (like country or OS/browser level checks), and correctly measure impact of your experiments on your metrics/events. At least one identifier, either userID or a Custom ID, is required to provide a consistent experience for a given user (as explained here). Besides userID, we also have email, ip, userAgent, country, locale and appVersion as top-level fields on StatsigUser. In addition, you can pass any key-value pairs in an object/dictionary to the custom field and be able to create targeting based on them. Note that while typing is lenient on the StatsigUser object to allow you to pass in numbers, strings, arrays, objects, and potentially even enums or classes, the evaluation operators will only be able to operate on primitive types - mostly strings and numbers. While we attempt to smartly cast custom field types to match the operator, we cannot guarantee evaluation results for other types. For example, setting an array as a custom field will only ever be compared as a string - there is no operator to match a value in that array.

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Private Attributes

Have sensitive user PII data that should not be logged? No problem, we have a solution for it! On the StatsigUser object we also have a field called privateAttributes, which is a simple object/dictionary that you can use to set private user attributes. Any attribute set in privateAttributes will only be used for evaluation/targeting, and removed from any logs before they are sent to Statsig server. For example, if you have feature gates that should only pass for users with emails ending in “@statsig.com”, but do not want to log your users’ email addresses to Statsig, you can simply add the key-value pair { email: "my_user@statsig.com" } to privateAttributes on the user and that’s it!

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Shutdown

To gracefully shutdown the SDK and ensure all events are flushed: 
await StatsigServer.Shutdown();
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