> ## Documentation Index
> Fetch the complete documentation index at: https://launchdarkly-preview.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Set up .NET (server-side) SDK

> Install and initialize the LaunchDarkly .NET (server-side) SDK

> For the complete documentation index, see [llms.txt](/llms.txt). For the full documentation snapshot, see [llms-full.txt](/llms-full.txt).

<div>
  <ReadmeButton sdk={SDK.DotNetServer} />

  <CursorButton sdk={SDK.DotNetServer} />
</div>

### Install the package

```shell title={"C#"} theme={null}
Install-Package LaunchDarkly.ServerSdk

```

### Initialize the SDK

```csharp title={".NET (server-side) SDK initialization"} theme={null}
using LaunchDarkly.Sdk;
using LaunchDarkly.Sdk.Server;

var builder = WebApplication.CreateBuilder(args);

// Set your LaunchDarkly SDK key.
// This is inlined as example only for onboarding.
// Never hardcode your SDK key in production.
var ldConfig = Configuration.Default("YOUR_SDK_KEY");
var client = new LdClient(ldConfig);

if (client.Initialized)
{
    // For onboarding purposes only we flush events as soon as
    // possible so we quickly detect your connection.
    // You don't have to do this in practice because events are automatically flushed.
    client.Flush();
    Console.WriteLine("*** SDK successfully initialized!\n");
}
else
{
    Console.WriteLine("*** SDK failed to initialize\n");
    Environment.Exit(1);
}

```

<Accordion title="Finding your SDK credentials">
  You can find your server-side SDK key, client-side ID, and mobile key in the "Resources" section of the help menu. Click the **help icon** at the bottom left corner of the LaunchDarkly UI, then choose **SDK keys**:

  <Frame caption="The SDK keys option in the help menu.">
    ![The SDK keys option in the help menu.](https://files.buildwithfern.com/https://launchdarkly.docs.buildwithfern.com/docs/28d3e1c568378ea02528db7ba62bfbd742f6f1cad964b5675395e10af5eeeb60/assets/images/auto/help-menu-sdk-keys.auto.png)
  </Frame>
</Accordion>

To learn more, read [Initialize the client](/sdk/server-side/dotnet#initialize-the-client) in the .NET (server-side) SDK reference guide.