The Calendar Service uses the Microsoft Graph API to access Office 365 calendar events. This API supports a broad range of operations with Office 365. However, the Calendar Service only uses a subset of commands that are related to calendar use cases.

Table 1. Operations currently used by Hybrid Calendar Services

Graph operation


POST /users/{id | userPrincipalName}/calendar/events

Add an event or meeting to a user's calendar.

GET /users/{id | userPrincipalName}/events/{id}

Retrieve details about a single event in a user's calendar.

GET /users/{id | userPrincipalName}/calendar/events/{id}/instances? startDateTime={start_datetime}&endDateTime={end_datetime}

Get the occurrences of a recurring meeting for a specified time range.

GET /users/{id | userPrincipalName}/calendar/events

Retrieve details about events in a user's calendar folder.

POST /subscriptions

Subscribe for notifications on changes to a user's calendar.

GET /users/{id|userPrincipalName}/mailboxSettings

Get a user's locale and out-of-office status.

DELETE /subscriptions/{id}

Unsubscribe from notifications on changes to a user's calendar.

PATCH /users/{id | userPrincipalName}/calendar/events/{id}

Update properties of calendar events (including join information and extended properties) in addition to other fields pertaining to the meeting.

POST /users/{id|userPrincipalName}/calendar/getSchedule

Displays the user availability and free/busy status for a specified time range.

DELETE /users/{id | userPrincipalName}/calendar/events/{id}

Deletes an event from a calendar.

POST /users/{id | userPrincipalName}/calendar/events/{id}/{accept | decline | tentativelyAccept}

Allows the user to accept/decline/tentatively-accept the status for a meeting.