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.NET Client SDK

Installation​

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

Initialize the SDK​

After installation, you will need to initialize the SDK using a Client SDK key from the "API Keys" tab on the Statsig console.

These Client SDK Keys are intended to be embedded in client side applications. If need be, you can invalidate or create new SDK Keys for other applications/SDK integrations.

info

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.

In addition to the SDK key, you should also pass in a StatsigUser for feature gate targeting and experimentation grouping purposes.

The 3rd parameter is optional and allows you to pass in a [StatsigOptions](#statsig-options) to customize the SDK.
using Statsig;
using Statsig.Client;

await StatsigClient.Initialize(
    "client-sdk-key",
    new StatsigUser { UserID = "some_user_id", Email = "user@email.com" },
    new StatsigOptions(new StatsigEnvironment(EnvironmentTier.Development)) // optional, use when needed to customize certain behaviors
);

Working with the SDK​

Checking a Feature Flag/Gate​

Now that your SDK is initialized, let's check 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.

if (StatsigClient.CheckGate("new_homepage_design"))
{
  // Gate is on, show new home page
}
else
{
  // Gate is off, show old home page
}

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. For example:

DynamicConfig config = StatsigClient.GetConfig("awesome_product_details");

// The 2nd parameter is the default value to be used in case the given parameter name does not exist on
// the Dynamic Config object. This can happen when there is a typo, or when the user is offline and the
// value has not been cached on the client.
string itemName = config.Get<string>("product_name", "Awesome Product v1");
double price = config.Get<double>("price", 10.0);
bool shouldDiscount = config.Get<bool>("discount", false);

Getting an 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

Layer layer = StatsigClient.GetLayer("user_promo_experiments");
var promoTitle = layer.Get("title", "Welcome to Statsig!");
var discount = layer.Get("discount", 0.1);

// or, via getExperiment

DynamicConfig  titleExperiment = StatsigClient.GetExperiment("new_user_promo_title");
DynamicConfig  priceExperiment = StatsigClient.GetExperiment("new_user_promo_price");

var promoTitle = titleExperiment.Get("title", "Welcome to Statsig!");
var discount = priceExperiment.Get("discount", 0.1);

...

double price = msrp * (1 - discount);

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 for the event, and you can additionally provide some value and/or an object of metadata to be logged together with the event:

StatsigClient.LogEvent(
    "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.

Statsig User​

You should provide a StatsigUser object whenever possible when initializing the SDK, passing as much information as possible in order to take advantage of advanced gate and config conditions (like country or OS/browser level checks).

Most of the time, the userID field is needed in order to provide a consistent experience for a given user (see logged-out experiments to understand how to correctly run experiments for logged-out users).

If the user is logged out at the SDK init time, you can leave the `userID` out for now, and we will use a stable device ID that we create and store in the local storage for targeting purposes.

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.

Once the user logs in or has an update/changed, make sure to call `updateUser` with the updated `userID` and/or any other updated user attributes:
// if you want to update the existing user, or change to a different user, call updateUser

await StatsigClient.UpdateUser(
    new StatsigUser { UserID = "new_user_id", Email = "new_user@email.com" },
);

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!

Statsig Options​

Initialize() takes an optional parameter options in addition to sdkKey and user that you can provide to customize the Statsig client. Here are the current options and we are always adding more to the list:

  • environment: StatsigEnvironment, default null

    • An object you can use to set environment variables that apply to all of your users in the same session and will be used for targeting purposes.
    • The most common usage is to set the environment tier (EnvironmentTier), e.g. new StatsigEnvironment(EnvironmentTier.Staging), and have feature gates pass/fail for specific environments.

  • ClientRequestTimeoutMs: int, default 0.

    • When set, the /initialize request will wait for a maximum of the specified ms before ignoring the request and considering the SDK initialized (relying on cached values or default values for checks to gates/experiments)

  • PersistentStorageFolder: string, default null

    • use this to specify a location for the persistent storage where the SDK will save cached values and logs.

  • ClientRequestTimeoutMs: int, default 0

    • use this to configure a timeout for the initialize request;
    • when the request times out, the SDK will serve cached or default values.

Shutting Statsig Down​

In order to save users' data and battery usage, as well as prevent logged events from being dropped, we keep event logs in client cache and flush periodically. Because of this, some events may not have been sent when your app shuts down.

To make sure all logged events are properly flushed or saved locally, you should tell Statsig to shutdown when your app is closing:

StatsigClient.Shutdown();

FAQ​

How do I run experiments for logged out users?​

See the guide on device level experiments