taskFileAttachment: createUploadSession

Namespace: microsoft.graph


APIs under the /beta version in Microsoft Graph are subject to change. Use of these APIs in production applications is not supported. To determine whether an API is available in v1.0, use the Version selector.

Create an upload session to iteratively upload ranges of a file as an attachment to a todoTask.

As part of the response, this action returns an upload URL that you can use in subsequent sequential PUT queries. The request headers for each PUT operation let you specify the exact range of bytes to be uploaded. This allows the transfer to be resumed, in case the network connection is dropped during the upload.

The following are the steps to attach a file to a Microsoft To Do task using an upload session:

  1. Create an upload session.
  2. Within that upload session, iteratively upload ranges of bytes (up to 4 MB each time) until all the bytes of the file have been uploaded, and the file is attached to the todoTask.
  3. Optional: Delete the upload session.

Note: Use this approach to attach a file of any supported size between 0 MB to 25 MB.

For an example that describes the end-to-end attachment process, see attach files to a To Do task.


One of the following permissions is required to call this API. To learn more, including how to choose permissions, see Permissions.

Permission type Permissions (from least to most privileged)
Delegated (work or school account) Tasks.ReadWrite
Delegated (personal Microsoft account) Tasks.ReadWrite
Application Tasks.ReadWrite.All

HTTP request

POST /me/todo/lists/{id}/tasks/{id}/attachments/createUploadSession
POST /users/{id}/todo/lists/{id}/tasks/{id}/attachments/createUploadSession

Request headers

Name Description
Authorization Bearer {token}. Required.
Content-Type application/json. Required.

Request body

In the request body, supply a JSON representation of the parameters.

The following table shows the parameter that can be used with this action.

Parameter Type Description
attachmentInfo attachmentInfo Represents attributes of the item to be uploaded and attached. At minimum, specify the attachment type (file), a name, and the size of the file.


If successful, this action returns a 200 OK response code and a new uploadSession in the response body.



The following is an example of a request to create an upload session.

POST https://graph.microsoft.com/v1.0/me/todo/lists/AAMDiFkfh=/tasks/AAMkADliMm=/attachments/createUploadSession
Content-Type: application/json

  "attachmentInfo": {
    "attachmentType": "file",
    "name": "flower",
    "size": 3483322


The following is an example of the response.

Note: The response object shown here might be shortened for readability.

HTTP/1.1 200 OK
Content-Type: application/json

    "@odata.context": "https://graph.microsoft.com/v1.0/$metadata#microsoft.graph.uploadSession",
    "uploadUrl": "https://graph.microsoft.com/v1.0/users/6f9a2a92-8527-4d64-837e-b5312852f36d/todo/lists/AAMDiFkfh=/tasks/AAMkADliMm=/attachmentSessions/AAMkADliMm=",
    "expirationDateTime": "2022-06-09T10:45:27.4324526Z",
    "nextExpectedRanges": [