Google Domains Dynamic DNS Updater

ScheduleGoogleDNSUpdate.ps1

$ScheduledJob = @{
    Name = 'DNS Updater'
    Trigger = New-JobTrigger -Once -RepetitionInterval 0:15 -RepeatIndefinitely -At 10:30
    Credential = (Get-Credential)
    ScriptBlock = {
        #Your info goes here
        $hostname = "HOSTNAME.com"

        $CurrentRecord = Resolve-DNSName -Name $hostname -Type A -Server 8.8.8.8 -DnsOnly | select -exp IPAddress

        #Get a page with your current IP
        $MyIp = Invoke-WebRequest "https://domains.google.com/checkip" | select -exp content

        #Make sure we got a IP back in the response
        If ($MyIp -match "(?:[0-9]{1,3}.){3}[0-9]{1,3}")
        {
            if ($MyIP -ne $CurrentRecord) {    # Only update the IP if it has changed
                $UpdateSplat = @{
			            #encode the username and password for the header
		            headers = @{
			            #Authorization =  "Basic {0}" -f ([System.Convert]::ToBase64String(([System.Text.Encoding]::ASCII.GetBytes(((Get-StoredCredential -CredName 'DomainUpdateCreds').GetNetworkCredential() | %{($_.UserName,$_.password) -join ':'})))))
			            Authorization =  "Basic {0}" -f ([System.Convert]::ToBase64String(([System.Text.Encoding]::ASCII.GetBytes((('USERNAMESTRING','PASSWORDSTRING') -join ':')))))
		            }
			            #Build up the URL
		            uri = "https://domains.google.com/nic/update?hostname={0}&myip={1}" -f $hostname, $MyIp
	            }
	
                #Invoke the URL
                $resp = Invoke-WebRequest @UpdateSplat
                $resp.Content #Expected answers that I found "good","nochg","nohost","badauth","notfqdn"
            } else {
                Write-Verbose -Message 'No Change' -Verbose
            }
        }
        Else
        {
          Write-Verbose -Message "No IP" -Verbose
        }
    }
}
Register-ScheduledJob @ScheduledJob

To use line 21 instead of line 22 install this dependency: https://www.powershellgallery.com/packages/StoredPSCredential/2.0.4.0

And then run this to initialize the credentials:

Initialize-StoredCredential -CredName 'DomainUpdateCreds'