I want to upload large files to SharePoint Online but I am unable to use chunked upload of sharepoint REST API. I would like to see a working example.

The api is described in here using the methods

startUpload(GUID, stream1) continueUpload(GUID, 10 MB, stream2)
continueUpload(GUID, 20 MB, stream3)
finishUpload(GUID, 30 MB, stream4)

I found the same question in https://social.msdn.microsoft.com/Forums/sqlserver/en-US/5596f87a-3155-4e4f-a6e8-8d38fa5e580d/office-365-onedrive-for-businesssharepoint-rest-api-startupload-command?forum=appsforsharepoint

but the solution uses C# and I need REST.

1 Answer 1


The following C# sample shows how to upload large file using the StartUpload, ContinueUpload, and FinishUpload REST endpoints:

using (var client = new WebClient())
    client.BaseAddress = webUri;
    client.Credentials = GetCredentials(webUri, userName, password);
    client.Headers.Add("X-FORMS_BASED_AUTH_ACCEPTED", "f");
    client.Headers.Add("X-RequestDigest", RequestFormDigest());

    var fileUrl = "/Documents/SharePoint User Guide.docx";
    var endpointUrlS = string.Format("{0}/_api/web/getfilebyserverrelativeurl('{1}')/savebinarystream", webUri, fileUrl);
    var fileContent = System.IO.File.ReadAllBytes(fileName);

    var firstChunk = true;
    var uploadId = Guid.NewGuid();
    var offset = 0L;
    const int chunkSize = 2048; //<-set chunk size (bytes)
    using (var inputStream = System.IO.File.OpenRead(fileName))
         var buffer = new byte[chunkSize];
         int bytesRead;
         while ((bytesRead = inputStream.Read(buffer, 0, buffer.Length)) > 0)
              if (firstChunk)
                  var endpointUrl = string.Format("{0}/_api/web/getfilebyserverrelativeurl('{1}')/startupload(uploadId=guid'{2}')", webUri, fileUrl,uploadId);
                  client.UploadData(endpointUrl, buffer);
                  firstChunk = false;                           
              else if (inputStream.Position == inputStream.Length)
                  var endpointUrl = string.Format("{0}/_api/web/getfilebyserverrelativeurl('{1}')/finishupload(uploadId=guid'{2}',fileOffset={3})", webUri, fileUrl, uploadId,offset);
                  var finalBuffer = new byte[bytesRead];
                  Array.Copy(buffer , finalBuffer , finalBuffer.Length);
                  client.UploadData(endpointUrl, finalBuffer);
                  var endpointUrl = string.Format("{0}/_api/web/getfilebyserverrelativeurl('{1}')/continueupload(uploadId=guid'{2}',fileOffset={3})", webUri, fileUrl, uploadId, offset);
                  client.UploadData(endpointUrl, buffer);
              offset += bytesRead;
              Console.WriteLine("%{0:P} completed", (((float)offset / (float)inputStream.Length) ));
  • For consuming SharePoint REST Interface WebClient class is utilized, in particular UploadData Method for uploading data.
  • GetCredentials.cs - method for getting SharePoint Online credentials
  • SharePoint REST POST requests requires form digest to be specified, RequestFormDigest is intended for that purpose (you could find the implementation of it here)


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  • 1
    I've tried this and I get the following error: /personal/tenant_awbrazier_onmicrosoft_com/Documents/largefile.zip does not exist. when it goes to do the first chunk. If I upload a file with the same name it then works
    – Webfort
    Commented May 24, 2016 at 11:23
  • 1
    I am looking same solution for REST API because I am using SharePoint online
    – Negi Rox
    Commented Feb 12, 2018 at 17:13
  • I am also getting that error when uploading the first chunk Commented Feb 7, 2023 at 17:19

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