Posted by on Sep 27, 2015 in #Office365Dev, Visual Studio | 1 comment

One of the greatest things about building Office Add-ins is the fact that they will run in Office Online (for instance Word Online, Excel Online and PowerPoint Online). Bringing your Office Add-ins across a large set of operating systems and devices.

Obviously we will need to test and make sure that our Office Add-in works in these different environments. As of right now, you can easily launch your Office (task-pane/content) Add-ins in Excel Online straight out of Visual Studio.

If you’re interested in launching your Office Add-in in any of the other Office Online applications, have a look here:

1. Get yourself an Office 365 tenant. If you don’t already have one, I would advise you to look into the Office 365 Developer Program:

2. Locate the URL of your Sharepoint site. This will be required by Visual Studio when uploading the Office Add-in manifest to your Office 365 tenant.


3. Head over to your Office Add-in solution in Visual Studio and get into the properties of the manifest project. Configure the Start Action to be a web browser instead of “Office Desktop Client”. Make sure to enter your Sharepoint site URL in the Site URL field.


At this point you will be asked to sign in with a user belonging to this Office 365 tenant. Make sure that this user has access to your Sharepoint site.

4. Before you can upload and launch your Office Add-in you’ll need to make sure that app side-loading is enabled for your Sharepoint site. By default it is not, and you will have to enable it using the SharePoint Online Management Shell. Download and install it:

5. Save and run the following PowerShell script (reference: in order to enable app side-loading for your Sharepoint site. Read more about enabling/disabling app side-loading and the risks associated with it at the link above.

$programFiles = [environment]::getfolderpath("programfiles")

add-type -Path $programFiles'\SharePoint Online Management Shell\' + <code>

Write-Host </code>
  'To enable SharePoint app sideLoading, ' + <code>
  'enter Site Url, username and password'

$siteurl = Read-Host 'Site Url'
$username = Read-Host &quot;User Name&quot;
$password = Read-Host -AsSecureString 'Password'

if ($siteurl -eq '') {
    $siteurl = ''
    $username = ''
    $password = ConvertTo-SecureString -String 'mypassword!'</code>
                -AsPlainText -Force
$outfilepath = $siteurl -replace ':', '_' -replace '/', '_'

    [Microsoft.SharePoint.Client.ClientContext]$cc = <code>
      New-Object Microsoft.SharePoint.Client.ClientContext($siteurl)

    [Microsoft.SharePoint.Client.SharePointOnlineCredentials]$spocreds = </code>
      New-Object <code>
      Microsoft.SharePoint.Client.SharePointOnlineCredentials($username, </code>

    $cc.Credentials = $spocreds
    $sideLoadingEnabled = <code>


    if($sideLoadingEnabled.value -eq $false) {
        Write-Host -ForegroundColor Yellow </code>
          'SideLoading feature is not enabled on the site:' $siteurl
        $site = $cc.Site;
            $sideLoadingGuid = <code>
           new-object System.Guid &quot;AE3A1339-61F5-4f8f-81A7-ABD2DA956A7D&quot;
            $site.Features.Add($sideLoadingGuid, $false, </code>
           Write-Host -ForegroundColor Green <code>
          'SideLoading feature enabled on site' $siteurl

    Else {
        Write-Host -ForegroundColor Green </code>
          'SideLoading feature is already enabled on site' $siteurl

Catch {
    Write-Host -ForegroundColor Red <code>
      'Error encountered when trying to enable SideLoading feature' </code>
      $siteurl, ':' $Error[0].ToString();

6. Now run your Office Add-in and experience it in the online world of Office! If Visual Studio doesn’t open your selected web browser – you can look into the build output and find the Office Add-in URL. Copy it and navigate to it in your web browser to get going!


-Simon Jäger