Working with the SharePoint Online REST service via PowerShell

Since SharePoint 2013 introduces a Representational State Transfer (REST) service that is comparable to the existing SharePoint client object models, it opens up a huge capabilities, in particular for administering and automating SharePoint Online when used with PowerShell.

My first idea was to utilize  Invoke-RestMethod cmdlet, which was introduced in Windows PowerShell 3.0.  Invoke-RestMethod cmdlet contains Credential parameter which could  accept basic, digest, NTLM, and Kerberos authentication.

SharePoint Client Component SDK comes with  a SharePointOnlineCredentials class  which represents an object that provides credentials to access SharePoint Online resources. But unfortunately SharePoint Online credentials could not be passed in Invoke-RestMethod cmdlet, since claims based authentication is not supported by this cmdlet.

Below is demonstrated a simplified PowerShell script  that to some extent mimics Invoke-RestMethod cmdlet. This script is intended for sending HTTPS request to a SharePoint Online REST service:

[Microsoft.PowerShell.Commands.WebRequestMethod]$Method = [Microsoft.PowerShell.Commands.WebRequestMethod]::Get,
Add-Type –Path "C:\Program Files\Common Files\microsoft shared\Web Server Extensions\15\ISAPI\Microsoft.SharePoint.Client.dll"
Add-Type –Path "C:\Program Files\Common Files\microsoft shared\Web Server Extensions\15\ISAPI\Microsoft.SharePoint.Client.Runtime.dll"
if([string]::IsNullOrEmpty($Password)) {
$SecurePassword = Read-Host Prompt "Enter the password" AsSecureString
else {
$SecurePassword = $Password | ConvertTo-SecureString AsPlainText Force
$credentials = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($UserName, $SecurePassword)
$request = [System.Net.WebRequest]::Create($Url)
$request.Credentials = $credentials
$request.Headers.Add("X-FORMS_BASED_AUTH_ACCEPTED", "f")
$request.Accept = "application/json;odata=verbose"
$response = $request.GetResponse()
$requestStream = $response.GetResponseStream()
$readStream = New-Object System.IO.StreamReader $requestStream
$results = $data | ConvertFrom-Json


#Example 1. Gets a value that specifies usage information about the site, including bandwidth, storage, and the number of visits to the site collection
$result = .\Invoke-RestSPO.ps1 Url "" UserName "" Password "password"
write-host 'Total amount of disk space, currently being used by the site collection (Mb):' ([math]::round($result.Usage.Storage /1Mb))
#Example 2. Get List Items
.\Invoke-RestSPO.ps1 Url "'Contacts')/title" UserName "" Password "password"