# New owner_email field on Microsoft calendars

Source: https://developer.nylas.com/docs/changelogs/2026-08-18-calendar-owner-email/

Microsoft calendars now come back with the email address of the account that owns them. Until now, `is_owned_by_user` told you whether a calendar belonged to the authenticated user, but nothing told you whose it was when the answer was no. That mattered for Microsoft grants, where a single user often has a dozen shared calendars in the same list response.

## Added

- **`owner_email` on the Calendar object** returns the email address of the account that owns the calendar. It appears on every Calendar response: [Get all Calendars](/docs/reference/api/calendar/get-all-calendars/), [Get Calendar](/docs/reference/api/calendar/get-calendars-id/), [Create Calendar](/docs/reference/api/calendar/create-calendar/), and [Update Calendar](/docs/reference/api/calendar/put-calendars-id/).

  ```json
  {
    "request_id": "2245305189-f1252288-9798-4e67-8201-xxxxcbdfc000",
    "data": {
      "name": "Calendar",
      "hex_color": "",
      "grant_id": "9564c95c-32f0-47cc-xxxx-fd1e961b910a",
      "id": "AAkALgAAAAAAHYQDEapmEc2byACqAC-EWg0ASdP2iK6fm0aDwISla-4q0QAAAAARxxxx",
      "object": "calendar",
      "is_primary": true,
      "read_only": false,
      "is_owned_by_user": true,
      "owner_email": "nyla@example.com"
    }
  }
  ```

- **`owner_email` in `calendar.created`, `calendar.updated`, and `calendar.deleted` notifications**, so you can attribute a shared calendar to its owner without a follow-up read. See the [Calendar notification reference](/docs/reference/notifications/calendar/).

## Notes

- Nylas returns `owner_email` for **Microsoft grants only**. Google, iCloud, EWS, and virtual calendars omit the field, so treat it as optional rather than assuming it's on every Calendar object.
- The field is read-only. You can't set or change it with a `PUT` request, the same as `is_owned_by_user`.

## Updated docs

- [Using the Calendar API](/docs/v3/calendar/#the-owner_email-field) explains the field, its Microsoft-only behavior, and how it pairs with `is_owned_by_user`.
- [Create and list calendars](/docs/cookbook/calendar/manage-calendars/) mentions it in the calendar flags section.