# Authorization

Availability queries and calendar events work on calendar accounts. Most
endpoints take an `access_token` for the account, or the account's `sub`, so
your application first needs authorization to the calendars it works with.
How Cronofy itself connects to each calendar service, and what calendar
administrators need to set up, is covered in
[Connect with Cronofy](https://docs.cronofy.com/connect/index.md).

<table class="table--definitions">
	<thead>
			<tr>
					<th>Method</th>
					<th>When it fits</th>
			</tr>
	</thead>
	<tbody>
			<tr>
					<td>[Individual Connect](https://docs.cronofy.com/developers/temporal-grid/connectivity/individual-connect/index.md)</td>
					<td>Each of your users connects their own calendars through an OAuth 2.0 flow. The default for most applications.</td>
			</tr>
			<tr>
					<td>[Enterprise Connect](https://docs.cronofy.com/developers/temporal-grid/connectivity/enterprise-connect/index.md)</td>
					<td>An administrator grants access to calendars across their domain, including resources such as meeting rooms, so users don't authorize one by one.</td>
			</tr>
			<tr>
					<td>[Organizational Unit with impersonation](https://docs.cronofy.com/api-reference/authorization/authentication/index.md)</td>
					<td>Your users' calendars are already connected to a Cronofy Organizational Unit. An [Internal Application](https://docs.cronofy.com/api-reference/application-management/internal-applications/index.md) acts for each member by passing their `sub` in the `Cronofy-Impersonate` header.</td>
			</tr>
			<tr>
					<td>[Application authentication](https://docs.cronofy.com/api-reference/authorization/authentication/index.md)</td>
					<td>Endpoints that aren't tied to one user, such as Availability queries across accounts, Bookable Events and Smart Invites, take the application's `client_secret`.</td>
			</tr>
	</tbody>
</table>
Whichever method you use, [Calendar Access Modes](https://docs.cronofy.com/developers/calendar-and-availability/access-modes/index.md)
and [Permissions](https://docs.cronofy.com/developers/temporal-grid/integration-approaches/permissions/index.md)
decide how much of each calendar your application can read and change.

Where there's no calendar to connect,
[Application Calendars](https://docs.cronofy.com/developers/calendar-and-availability/calendar-events/application-calendars/index.md)
give your application an account of its own.



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