Sharepoint - Is it possible to create site collection using CSOM?

Tenant.CreateSite method queues a site collection for creation with the specified properties. Tenant class is a part of Microsoft.Online.SharePoint.Client.Tenant.dll (SharePoint Online Management Shell)

How to create site collection via CSOM in SharePoint 2013

using System;
using System.Security;
using Microsoft.Online.SharePoint.TenantAdministration;
using Microsoft.SharePoint.Client;

namespace CSOMProvisioning
{
    class Program
    {
        static void Main(string[] args)
        {

            const string username = "[email protected]";
            const string password = "password";
            const string tenantAdminUrl = "https://contoso-admin.sharepoint.com/";
            var securedPassword = new SecureString();
            foreach (var c in password.ToCharArray()) securedPassword.AppendChar(c);
            var credentials = new SharePointOnlineCredentials(username, securedPassword);



            using (var context = new ClientContext(tenantAdminUrl))
            {
                context.Credentials = credentials;
                CreateSite(context, "https://contoso.sharepoint.com/sites/marketing","Marketing");
            }

        }


        /// <summary>
        /// Create a new site.
        /// </summary>
        /// <param name="context"></param>
        /// <param name="url">rootsite + "/" + managedPath + "/" + sitename: e.g. "https://auto.contoso.com/sites/site1"</param>
        /// <param name="title">site title: e.g. "Test Site"</param>
        /// <param name="owner">site owner: e.g. [email protected]</param>
        /// <param name="template">The site template used to create this new site</param>
        /// <param name="localeId"></param>
        /// <param name="compatibilityLevel"></param>
        /// <param name="storageQuota"></param>
        /// <param name="resourceQuota"></param>
        /// <param name="timeZoneId"></param>
        internal static void CreateSite(ClientContext context, String url, String owner, String title =null, String template = null, uint? localeId = null, int? compatibilityLevel = null, long? storageQuota = null, double? resourceQuota = null, int? timeZoneId = null)
        {
            var tenant = new Tenant(context);

            if (url == null)
                throw new ArgumentException("Site Url must be specified");

            if (string.IsNullOrEmpty(owner))
                throw new ArgumentException("Site Owner must be specified");

            var siteCreationProperties = new SiteCreationProperties {Url = url, Owner = owner};
            if (!string.IsNullOrEmpty(template))
                siteCreationProperties.Template = template;
            if (!string.IsNullOrEmpty(title))
                siteCreationProperties.Title = title;
            if (localeId.HasValue)
                siteCreationProperties.Lcid = localeId.Value;
            if (compatibilityLevel.HasValue)
                siteCreationProperties.CompatibilityLevel = compatibilityLevel.Value;
            if (storageQuota.HasValue)
                siteCreationProperties.StorageMaximumLevel = storageQuota.Value;
            if (resourceQuota.HasValue)
                siteCreationProperties.UserCodeMaximumLevel = resourceQuota.Value;
            if (timeZoneId.HasValue)
                siteCreationProperties.TimeZoneId = timeZoneId.Value;
            var siteOp = tenant.CreateSite(siteCreationProperties);
            context.Load(siteOp);
            context.ExecuteQuery();

        }



    }
}

This example is taken from a SharePoint Online environment with provided hosted apps in mind. Creating a console application, adding reference to

• Microsoft.SharePoint.Client.dll
• Microsoft.SharePoint.Client.Runtime.dll
• Microsoft.Online.SharePoint.Client.Tenant.dll

and pasting this snippet to the main method should do the trick.

var SHAREPOINT_PID = "00000003-0000-0ff1-ce00-000000000000"; // SharePoint constant
var tenantAdminUri = new Uri("https://<TENANT>-admin.sharepoint.com");
var token = TokenHelper.GetAppOnlyAccessToken(SHAREPOINT_PID, tenantAdminUri.Authority, null).AccessToken;

using (var context = TokenHelper.GetClientContextWithAccessToken(tenantAdminUri.ToString(), token))
{
    var tenant = new Tenant(context);
    var properties = new SiteCreationProperties()
    {
        Url = "https://<TENANT>.sharepoint.com/sites/site1",
        Owner = "<USER>@<TENANT>.onmicrosoft.com",
        Template = "STS#0",
        StorageMaximumLevel = 1000,
        UserCodeMaximumLevel = 300
    };
    tenant.CreateSite(properties);

    context.Load(tenant);
    context.ExecuteQuery();
}

In this example I’ve created a simple console application but it might as well be a service running in Azure or any other .NET application.

Reference: Create Site Collections in SharePoint Online using CSOM

I know you asked for CSOM, but in case it helps anyone, I was able to do this in PowerShell using the CreateSite method of the Admin web service against on-prem SP2013. You can call DeleteSite similarly (it's simpler as it has only one parameter). I started out down the route of creating a tenant administration site for my on-prem SP2013 but was having authentication issues. This was a good fallback approach for me (does everything I need it to).

The inputs to the script are as follows:

• $user - farm admin login (I am also using this as the owner of the new site collection)
• $pwd - farm admin pwd
• $adminSiteUrl - central admin site URL (must be accessible from the box where this script is running)
• $siteUrl - the full URL of the new site collection to be created
• $siteTitle - the title of the new site collection
• $username - the display name of the new site collection owner

Here's the PowerShell:

$securePwd = ConvertTo-SecureString $pwd -AsPlainText -Force
$cred = New-Object PSCredential($user, $securePwd)
$wsdlUrl = $adminSiteUrl + "/_vti_adm/Admin.asmx?WSDL"
$svc = New-WebServiceProxy -Uri $wsdlUrl -Credential $cred
$svc.CreateSite(
    $siteUrl,   # URL
    $siteTitle, # Title
    "",         # Description
    1033,       # LCID
    "STS#0",    # WebTemplate
    $user,      # Owner Login
    $userName,  # Owner Name
    "",         # Owner Email
    "",         # PortalUrl
    "")         # PortalName