Add User to group in batch with Graph

AddUserToGroupWithGraph.ps1

#You need Powershell API module @ https://github.com/poiriersimon/PowershellAPIModule
Import-Module "C:\Modules\PowershellAPI\PowershellAPI.psd1"
$AdminAccount = "user@domain.com"
$clientid = "1b730954-1685-4b74-9bfd-dac224a7b894";
$RessourceURI = "https://graph.windows.net";
$RedirectURI = "urn:ietf:wg:oauth:2.0:oob";

#FindGroupId
$Groupids = Invoke-GraphApi -Resource groups -UserPrincipalName $AdminAccount -ClientID $Clientid -redirectUri $RedirectURI | select Displayname,id
# Choose une from here Need to be a Office 365 group or a security group based on https://docs.microsoft.com/en-us/graph/api/group-post-members?view=graph-rest-1.0&tabs=http

$GroupID = "2fddd7e5-eed3-41ef-8a2a-555fea462451"
$Users =  Invoke-GraphApi -Resource users -UserPrincipalName $AdminAccount -ClientID $Clientid -redirectUri $RedirectURI |where{$_.userprincipalname -like "user*"} |select userprincipalname

##Batch Request 
$Batchheaders = [pscustomobject]@{
    "Content-Type" = "application/json"
}
$myBatchRequests = @()
[int]$requestID = 0

Foreach($user in $users){
    $requestID ++
    $BBody =  [pscustomobject]@{
        "@odata.id" = "https://graph.microsoft.com/v1.0/users/$($user.userprincipalname)"
        }
    $myRequest = [pscustomobject][ordered]@{ 
        url    = "/groups/$GroupID/members/`$ref"
        method = "POST"
        id     = $requestID
        body = $BBody
        headers = $Batchheaders
    }
    $myBatchRequests += $myRequest
}

$allBatchRequests = @()
$allBatchRequests +=  [pscustomobject][ordered]@{ 
    requests = $myBatchRequests
}

$batchBody = $allBatchRequests | ConvertTo-Json -Depth 4
$Result = Invoke-GraphApi -Resource `$batch -UserPrincipalName $AdminAccount -ClientID $Clientid -redirectUri $RedirectURI -Body $batchBody -Method Post
$Result.responses

#If Error
$Result.responses |select -ExpandProperty body | select -ExpandProperty error | fl message