This is a quick blog post with an example PowerShell cmdlet allowing you to find out what type of authentication and branding exists for a domain in Azure AD.
function Get-AzureADDomainInfoFromPublicApi
{
[CmdletBinding()]
[Alias()]
Param
(
# Param1 help description
[Parameter(Mandatory=$true,
ValueFromPipeline=$true,
Position=0)]
[String] $Domain
)
Begin
{
}
Process
{
$Url = "https://login.microsoftonline.com/common/userrealm/?user=someone.random@" + $Domain + "&checkForMicrosoftAccount=true&api-version=2.1"
Invoke-RestMethod $Url
}
End
{
}
}
Get-AzureADDomainInfoFromPublicApi microsoft.com
Get-AzureADDomainInfoFromPublicApi innofactor.com
For example, in the output, if “AuthURL” contains a url you’ll see that ADFS is used and if is_dsso_enabled that means the Seamless SSO is active.
Good Workaround! 
Thank you for the write-up. I’m trying to find documentation that outlines more detail about each of the returned values (e.g., MicrosoftAccount, IsMicrosoftAccountSet, etc.) but can’t seem to locate it. For example, what is a value of 1 for “MicrosoftAccount” versus a value of 0. At first, I assumed 0 meant there was no account, but that can’t be correct as “IsMicrosoftAccountSet” comes back as True.
Do you have any recommendations?