import { InstallCardLink } from "@site/src/components/InstallCardLink"; import { StepByStep, Step, StepText, StepCode } from "@site/src/components/Steps";

Get a SpacetimeDB C# app running in under 5 minutes.

Prerequisites

.NET 8 SDK installed
SpacetimeDB CLI installed

<StepByStep> <Step title="Install .NET WASI workload"> <StepText> SpacetimeDB C# modules compile to WebAssembly using the WASI experimental workload. </StepText> <StepCode> ```bash dotnet workload install wasi-experimental ``` </StepCode> </Step> <Step title="Create your project"> <StepText> Run the `spacetime dev` command to create a new project with a C# SpacetimeDB module.

  This will start the local SpacetimeDB server, compile and publish your module, and generate C# client bindings.
</StepText>
<StepCode>

bash

spacetime dev --template basic-cs

</StepCode>

</Step> <Step title="Explore the project structure"> <StepText> Your project contains both server and client code.

  Edit `spacetimedb/Lib.cs` to add tables and reducers. Use the generated bindings in the client project.
</StepText>
<StepCode>

my-spacetime-app/
├── spacetimedb/             # Your SpacetimeDB module
│   ├── StdbModule.csproj
│   └── Lib.cs               # Server-side logic
├── client.csproj
├── Program.cs               # Client application
└── module_bindings/         # Auto-generated types

</StepCode>

</Step> <Step title="Understand tables and reducers"> <StepText> Open `spacetimedb/Lib.cs` to see the module code. The template includes a `Person` table and two reducers: `Add` to insert a person, and `SayHello` to greet everyone.

  Tables store your data. Reducers are functions that modify data — they're the only way to write to the database.
</StepText>
<StepCode>

csharp

using SpacetimeDB;

public static partial class Module
{
    [SpacetimeDB.Table(Accessor = "Person", Public = true)]
    public partial struct Person
    {
        public string Name;
    }

    [SpacetimeDB.Reducer]
    public static void Add(ReducerContext ctx, string name)
    {
        ctx.Db.Person.Insert(new Person { Name = name });
    }

    [SpacetimeDB.Reducer]
    public static void SayHello(ReducerContext ctx)
    {
        foreach (var person in ctx.Db.Person.Iter())
        {
            Log.Info($"Hello, {person.Name}!");
        }
        Log.Info("Hello, World!");
    }
}

</StepCode>

</Step> <Step title="Test with the CLI"> <StepText> Open a new terminal and navigate to your project directory. Then use the SpacetimeDB CLI to call reducers and query your data directly. </StepText> <StepCode> ```bash cd my-spacetime-app

Call the add reducer to insert a person

spacetime call add Alice

Query the person table

spacetime sql "SELECT * FROM Person" name

"Alice"

Call say_hello to greet everyone

spacetime call say_hello

View the module logs

spacetime logs 2025-01-13T12:00:00.000000Z INFO: Hello, Alice! 2025-01-13T12:00:00.000000Z INFO: Hello, World!

    </StepCode>
  </Step>
</StepByStep>

## Next steps

- See the [Chat App Tutorial](../00300-tutorials/00100-chat-app.md) for a complete example
- Read the [C# SDK Reference](../../00200-core-concepts/00600-clients/00600-csharp-reference.md) for detailed API docs