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.NET Runtime¶

This reference covers runtime versions, worker configuration, target framework choices, and package dependencies for Azure Functions .NET apps.

Main Content¶

Supported runtimes and models¶

Model	Supported .NET versions	Recommended for new apps
Isolated worker	.NET 10, .NET 9, .NET 8, .NET Framework 4.8.1	Yes
In-process	.NET 8 only	No

flowchart LR
    A[.NET 8 LTS] --> B[Isolated worker]
    C[.NET 9 STS] --> B
    D[In-process] --> E[.NET 8 only]

Required app settings¶

Setting	Value	Purpose
`FUNCTIONS_WORKER_RUNTIME`	`dotnet-isolated`	Selects isolated worker runtime
`FUNCTIONS_EXTENSION_VERSION`	`~4`	Pins Functions runtime major version
`AzureWebJobsStorage`	connection string or identity-based settings	Required host storage

az functionapp config appsettings set   --name "$APP_NAME"   --resource-group "$RG"   --settings "FUNCTIONS_WORKER_RUNTIME=dotnet-isolated" "FUNCTIONS_EXTENSION_VERSION=~4"

csproj baseline¶

Use net8.0 as the default target framework for production workloads:

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>net8.0</TargetFramework>
    <AzureFunctionsVersion>v4</AzureFunctionsVersion>
    <OutputType>Exe</OutputType>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.Azure.Functions.Worker" Version="1.*" />
    <PackageReference Include="Microsoft.Azure.Functions.Worker.Sdk" Version="1.*" OutputItemType="Analyzer" />
    <PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.Http" Version="3.*" />
    <PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.Http.AspNetCore" Version="1.*" />
    <PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.Storage" Version="6.*" />
    <PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.Timer" Version="4.*" />
    <PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.CosmosDB" Version="4.*" />
  </ItemGroup>
</Project>

Build and publish commands¶

dotnet build
dotnet publish --configuration Release --output ./publish
func azure functionapp publish "$APP_NAME"

Use runtime-safe creation flags when provisioning:

az functionapp create   --name "$APP_NAME"   --resource-group "$RG"   --storage-account "$STORAGE_NAME"   --runtime dotnet-isolated   --runtime-version 8   --functions-version 4   --os-type Linux

Upgrade guidance¶

Move startup logic into Program.cs with HostBuilder.
Replace in-process HTTP abstractions with HttpRequestData and HttpResponseData.
Replace context.GetLogger() with constructor-injected ILogger<T>.
Update trigger attributes and extension packages to isolated-worker equivalents.

See Also¶

Sources¶