---
url: https://jasperfx.github.io/alba/guide/bootstrapping.md
description: >-
  Bootstrap Alba from an IHostBuilder or with StartAlbaAsync to test
  Startup.cs-style ASP.NET Core applications, including on .NET 11.
---

# Alternative Bootstrapping Methods

Whilst `AlbaHost.For<T>` is the preferred way of bootstrapping, other options exist in Alba to cover some older & alternative scenarios.

## Initializing AlbaHost with IHostBuilder Directly

To bootstrap a **ASP.NET Core Startup.cs-style** application, create a `AlbaHost` using the definition of your `IHostBuilder` as shown below.
On .NET 11 this is the way to test a `Startup.cs`-style application, because `AlbaHost.For<T>` only supports applications built
with `WebApplicationBuilder` there.

```cs
[Fact]
public async Task build_host_from_Program()    
{
    // Bootstrap your application just as your real application does
    var hostBuilder = Program.CreateHostBuilder(Array.Empty<string>());

    await using var host = await AlbaHost.For(hostBuilder);

    // Just as a sample, I'll run a scenario against
    // a "hello, world" application's root url
    await host.Scenario(s =>
    {
        s.Get.Url("/");
        s.ContentShouldBe("Hello, World!");
    });
}
```

snippet source | anchor

::: tip
Bootstrapping an `AlbaHost` is asynchronous. Use your test framework's asynchronous
initialization support (e.g. xUnit's `IAsyncLifetime`) to start the host.
:::

Or alternatively, you can use one of the Alba extension methods off of `IHostBuilder` to start an `AlbaHost` object in a fluent interface
style:

```cs
[Fact]
public async Task fluent_interface_bootstrapping()    
{
    await using var host = await Program
        .CreateHostBuilder(Array.Empty<string>())
        .StartAlbaAsync();

    // Just as a sample, I'll run a scenario against
    // a "hello, world" application's root url
    await host.Scenario(s =>
    {
        s.Get.Url("/");
        s.ContentShouldBe("Hello, World!");
    });
}
```

snippet source | anchor

The `AlbaHost` is an extension of the standard .Net Core [IHost](https://learn.microsoft.com/en-us/dotnet/api/microsoft.extensions.hosting.ihost) interface with a few additions for testing support.
While you can always access the underlying `TestServer` through the `IAlbaHost.Server` property, you're mostly going to be using the `Scenario()` method to write Alba "Scenario" tests.

::: tip
Every bootstrapping method returns an `AlbaHostBuilder`, so configuration values, service registrations, and extensions can be
chained on before the host is awaited. See [Configuring the Host Fluently](gettingstarted.md#configuring-the-host-fluently).
:::