That's the minimum giraffe sample?

lolkek.fsproj

<Project Sdk="Microsoft.NET.Sdk.Web">

    <PropertyGroup>
        <OutputType>Exe</OutputType>
        <TargetFramework>net5.0</TargetFramework>
    </PropertyGroup>

    <ItemGroup>
        <Compile Include="Program.fs" />
    </ItemGroup>

    <ItemGroup>
      <PackageReference Include="Giraffe" Version="5.0.0-rc-6" />
    </ItemGroup>

</Project>

Program.fs

open Microsoft.AspNetCore
open Microsoft.AspNetCore.Hosting
open Giraffe

WebHost
    .CreateDefaultBuilder()
    .UseKestrel()
    .Configure(fun a -> a.UseGiraffe(route "/" >=> POST >=> bindJson json))
    .ConfigureServices(fun s -> s.AddGiraffe() |> ignore)
    .Build()
    .Run()