heroku/dotnet is the Heroku Cloud Native Buildpack for .NET and ASP.NET Core applications. It builds .NET and ASP.NET Core application source code into application images with minimal configuration.

To build a .NET application codebase into a production image:

$ cd ~/workdir/sample-dotnet-app
$ pack build sample-app --builder heroku/builder:24

Then run the image:

docker run --rm -it -e "PORT=8080" -p 8080:8080 sample-app

A solution file (e.g. MySolution.sln) or .NET project file (e.g. *.csproj, *.vbproj or *.fsproj) must be present in the application’s root directory. If the root directory contains both solution and project files, the solution file will be preferred for the build and publish process.

The buildpack support C#, Visual Basic and F# projects using the .NET and ASP.NET Core frameworks (version 8.0 and up).

By default, the buildpack will install the latest available .NET SDK based on the value of the TargetFramework property, which must be set in each project file. TFM values that follow the net{major_version}.0 format are currently supported (e.g. net6.0, net7.0, net8.0). If a solution references projects that target different framework versions, the most recent version will be preferred when inferring the .NET SDK version to install.

To install a different .NET SDK version, add a global.json file to the root directory. The buildpack supports specifying both the version and rollForward policy to define which .NET SDK version to install. For instance, to install a specific version a global.json file may look like this:

{
  "sdk": {
    "version": "8.0.106",
    "rollForward": "disable"
  }
}

A complete inventory of supported .NET SDK versions and platforms is available here.

Issues and pull requests are welcome. See our contributing guidelines if you would like to help.