# Building and testing Xamarin applications

Learn how to create a continuous integration (CI) workflow in GitHub Actions to build and test your Xamarin application.

## Introduction

This guide shows you how to create a workflow that performs continuous integration (CI) for your Xamarin project. The workflow you create will allow you to see when commits to a pull request cause build or test failures against your default branch; this approach can help ensure that your code is always healthy.

For a full list of available Xamarin SDK versions on the GitHub Actions-hosted macOS runners, see the README file for the version of macOS you want to use in the [GitHub Actions Runner Images repository](https://github.com/actions/runner-images/tree/main/images/macos).

## Prerequisites

We recommend that you have a basic understanding of Xamarin, .NET Core SDK, YAML, workflow configuration options, and how to create a workflow file. For more information, see:

* [Workflow syntax for GitHub Actions](/en/actions/using-workflows/workflow-syntax-for-github-actions)
* [Getting started with .NET](https://dotnet.microsoft.com/learn)
* [Learn Xamarin](https://dotnet.microsoft.com/learn/xamarin)

## Building Xamarin.iOS apps

The example below demonstrates how to change the default Xamarin SDK versions and build a Xamarin.iOS application.

```yaml
name: Build Xamarin.iOS app

on: [push]

jobs:
  build:

    runs-on: macos-latest

    steps:
    - uses: actions/checkout@v6
    - name: Set default Xamarin SDK versions
      run: |
        $VM_ASSETS/select-xamarin-sdk-v2.sh --mono=6.12 --ios=14.10

    - name: Set default Xcode 12.3
      run: |
        XCODE_ROOT=/Applications/Xcode_12.3.0.app
        echo "MD_APPLE_SDK_ROOT=$XCODE_ROOT" >> $GITHUB_ENV
        sudo xcode-select -s $XCODE_ROOT

    - name: Setup .NET Core SDK 5.0.x
      uses: actions/setup-dotnet@v4
      with:
        dotnet-version: '5.0.x'

    - name: Install dependencies
      run: nuget restore <sln_file_path>

    - name: Build
      run: msbuild <csproj_file_path> /p:Configuration=Debug /p:Platform=iPhoneSimulator /t:Rebuild
```

## Building Xamarin.Android apps

The example below demonstrates how to change default Xamarin SDK versions and build a Xamarin.Android application.

```yaml
name: Build Xamarin.Android app

on: [push]

jobs:
  build:

    runs-on: macos-latest

    steps:
    - uses: actions/checkout@v6
    - name: Set default Xamarin SDK versions
      run: |
        $VM_ASSETS/select-xamarin-sdk-v2.sh --mono=6.10 --android=10.2

    - name: Setup .NET Core SDK 5.0.x
      uses: actions/setup-dotnet@v4
      with:
        dotnet-version: '5.0.x'

    - name: Install dependencies
      run: nuget restore <sln_file_path>

    - name: Build
      run: msbuild <csproj_file_path> /t:PackageForAndroid /p:Configuration=Debug
```

## Specifying a .NET version

To use a preinstalled version of the .NET Core SDK on a GitHub-hosted runner, use the `setup-dotnet` action. This action finds a specific version of .NET from the tools cache on each runner, and adds the necessary binaries to `PATH`. These changes will persist for the remainder of the job.

The `setup-dotnet` action is the recommended way of using .NET with GitHub Actions, because it ensures consistent behavior across different runners and different versions of .NET. If you are using a self-hosted runner, you must install .NET and add it to `PATH`. For more information, see the [`setup-dotnet`](https://github.com/marketplace/actions/setup-net-core-sdk) action.