# Amazon GameLift Servers Realtime client API (C\$1) reference
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Use this reference guide to understand how to implement Realtime client API functionality into your multiplayer game clients. For guidance on how to integrate this API into your game clients, see [Integrate a game client for Amazon GameLift Servers Realtime](realtime-client.md).

The Realtime client API includes a set of synchronous API calls and asynchronous callbacks that enable a game client to connect to a Realtime server and exchange messages and data with other game clients via the server. 

This API is defined in the following libraries: 

Client.cs 
+ [Synchronous actions](realtime-sdk-csharp-ref-actions.md)
+ [Asynchronous callbacks](realtime-sdk-csharp-ref-callbacks.md)
+ [Data types](realtime-sdk-csharp-ref-datatypes.md)

**To set up the Realtime client API**

1. **Download the [Amazon GameLift ServersRealtime client SDK](https://aws.amazon.com/gamelift/getting-started).** 

1. **Build the C\$1 SDK libraries.** Locate the solution file `GameLiftRealtimeClientSdkNet45.sln`. See the `README.md` file for the C\$1 Server SDK for minimum requirements and additional build options. In an IDE, load the solution file. To generate the SDK libraries, restore the NuGet packages and build the solution.

1. **Add the Realtime Client libraries to your game client project.**