event: delta

Namespace: microsoft.graph

Get a set of event resources that have been added, deleted, or updated in a calendarView (a range of events defined by start and end dates) of the user's primary calendar.

Typically, synchronizing events in a calendarView in a local store entails a round of multiple delta function calls. The initial call is a full synchronization, and every subsequent delta call in the same round gets the incremental changes (additions, deletions, or updates). This allows you to maintain and synchronize a local store of events in the specified calendarView, without having to fetch all the events of that calendar from the server every time.


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) Calendars.Read
Delegated (personal Microsoft account) Calendars.Read
Application Calendars.Read

HTTP request

GET /me/calendarView/delta?startDateTime={start_datetime}&endDateTime={end_datetime}
GET /users/{id}/calendarView/delta?startDateTime={start_datetime}&endDateTime={end_datetime}

Query parameters

Tracking changes in events incurs a round of one or more delta function calls. If you use any query parameter (other than $deltatoken and $skiptoken), you must specify it in the initial delta request. Microsoft Graph automatically encodes any specified parameters into the token portion of the @odata.nextLink or @odata.deltaLink URL provided in the response. You only need to specify any desired query parameters once upfront. In subsequent requests, simply copy and apply the @odata.nextLink or @odata.deltaLink URL from the previous response, as that URL already includes the encoded, desired parameters.

Query parameter Type Description
startDateTime String The start date and time of the time range, represented in ISO 8601 format. For example, "2015-11-08T19:00:00.0000000".
endDateTime String The end date and time of the time range, represented in ISO 8601 format. For example, "2015-11-08T20:00:00.0000000".
$deltatoken string A state token returned in the @odata.deltaLink URL of the previous delta function call for the same calendar view, indicating the completion of that round of change tracking. Save and apply the entire @odata.deltaLink URL including this token in the first request of the next round of change tracking for that calendar view.
$skiptoken string A state token returned in the @odata.nextLink URL of the previous delta function call, indicating there are further changes to be tracked in the same calendar view.

OData query parameters

  • Expect a delta function call on a calendarView to return the same properties you'd normally get from a GET /calendarview request. You cannot use $select to get only a subset of those properties.

  • There are other OData query parameters that the delta function for calendarView doesn't support: $expand, $filter,$orderby, and $search.

Request headers

Name Type Description
Authorization string Bearer {token}. Required.
Content-Type string application/json. Required.
Prefer string odata.maxpagesize={x}. Optional.
Prefer string {Time zone}. Optional, UTC assumed if absent.


If successful, this method returns a 200 OK response code and event collection object in the response body.

Within a round of delta function calls bound by the date range of a calendarView, you may find a delta call returning two types of events under @removed with the reason deleted:

  • Events that are within the date range and that have been deleted since the previous delta call.
  • Events that are outside the date range and that have been added, deleted, or updated since the the previous delta call.

Filter the events under @removed for the date range that your scenario requires.



The following example shows how to make a single delta function call, and limit the maximum number of events in the response body to 2.

To track changes in a calendar view, you would make one or more delta function calls, with appropriate state tokens, to get the set of incremental changes since the last delta query.

GET https://graph.microsoft.com/v1.0/me/calendarView/delta?startdatetime={start_datetime}&enddatetime={end_datetime}

Prefer: odata.maxpagesize=2

If the request is successful, the response would include a state token, which is either a skipToken (in an @odata.nextLink response header) or a deltaToken (in an @odata.deltaLink response header). Respectively, they indicate whether you should continue with the round or you have completed getting all the changes for that round.

The response below shows a skipToken in an @odata.nextLink response header.

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

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

  "value": [
      "originalStartTimeZone": "originalStartTimeZone-value",
      "originalEndTimeZone": "originalEndTimeZone-value",
      "responseStatus": {
        "response": "response-value",
        "time": "datetime-value"
      "transactionId": null,
      "iCalUId": "iCalUId-value",
      "reminderMinutesBeforeStart": 99,
      "isDraft": false,
      "isReminderOn": true

See also