Zoom Calendaring Overview

Zoom delivers the best experience to users when calendaring integration is enabled for user accounts, Zoom Rooms, and H.323 or SIP room systems.

What are the benefits of enabling calendaring integration?

• Users see a full calendar (including non-Zoom meetings) in their Zoom apps

• Users can schedule and edit meetings from their Zoom apps

• Zoom Rooms screens and scheduling displays show upcoming calendar events

• Standards-based H.323 and SIP endpoints can join Zoom meetings automatically or with one touch through the Enhanced API connector

Bi-Directional Sync is recommended and enabled by default when calendar integration is active. With Bi-Directional Sync, the integration covers both Zoom and non-Zoom calendar events, providing a unified experience for users who rely on Zoom as their central scheduling hub.

Enabling Bi-Directional Calendar Sync ensures any third-party calendar events that are deleted, edited, or abandoned during scheduling are synced with the Zoom Web Calendaring Service automatically

Which calendaring providers are supported?

Zoom customers can integrate contact and calendar data with three providers:

• Microsoft 365 (formerly Office 365)

• Microsoft Exchange Server

• Google Workspace

How does the calendaring integration work?

Zoom's calendaring integration follows four stages: authorization, event monitoring, endpoint data retrieval, and Bi-Directional Sync. The first two stages are universal across all endpoints and methods. The third stage differs depending on the endpoint type and the selected authentication method.

1

Authorization and secure credential storage

Zoom administrators — or users, if allowed by the organization — must first authorize access to their calendaring provider through the Zoom Web Portal.

Zoom stores the objects required to access the connected calendar in a persistent, encrypted, and secure location. When using OAuth 2.0, Zoom securely stores access tokens and delegated access refresh tokens in the Zoom Cloud. However, for on-premises Exchange (non-hybrid), which doesn't support OAuth 2.0, Zoom must securely store the username and password in the Zoom Cloud, as this is the only available method to maintain access.

Direct integration to Exchange On-Premises requires Basic authentication.

You can optionally configure calendaring integrations to use Zoom Customer Managed Key (CMK) to encrypt and store credentials, enabling you to protect certain data stored at rest within the Zoom Cloud infrastructure using your own encryption keys. CMK is a paid offering and Zoom's Bring Your Own Key (BYOK) solution. You can read more about Zoom CMK on the Zoom website.

2

Event monitoring and change notification

The Zoom Web Calendaring Service subscribes to a webhook from the calendaring provider for each user after the calendar is connected in the web portal. These webhooks notify the Web Calendaring Service of any calendar changes so it can then notify the appropriate Zoom endpoints that an update is needed.

3

Endpoint data retrieval

How calendar data reaches a Zoom endpoint depends on the endpoint type and the selected authentication method. The following sections describe each model.

Desktop and mobile apps: Delegated access

When using delegated access, the Zoom Web Calendaring Service passes the OAuth access token to the desktop or mobile client at sign-in. The client holds this token temporarily in memory and uses it to connect directly to the calendaring provider to retrieve event data. If the access token is invalid, the Zoom Web Calendaring Service uses the stored refresh token to request a new access token and passes it to the client.

Desktop and mobile apps: Application Permissions (Microsoft Graph API)

When using the Application Permissions method, access tokens remain in the Zoom Cloud and aren't passed to client devices. Instead, all calendar data requests are proxied through the Zoom Web Calendaring Service on behalf of the client. The client doesn't connect directly to the calendaring provider.

Zoom Rooms: Both methods

Regardless of whether Application Permissions or Full Delegate Access is used, Zoom Rooms store tokens both in the Zoom Cloud and locally on the Zoom Room endpoint. Zoom Rooms connect directly to the calendaring provider to retrieve calendar data.

The diagrams on the Provider-Specific Details page illustrate the Delegated and Application-based Microsoft Graph API methods for user desktop and mobile integrations. Zoom Rooms follow a different token storage and retrieval model as described above.

4

Bi-Directional Calendar Sync

With Bi-Directional Calendar Sync enabled, if a user schedules or updates a meeting from a Zoom client or the web, the Web Calendaring Service creates or updates the event on the user's calendar through the calendar service provider's API.

Admins can configure Bi-Directional Sync on an account or user group level.

Bi-Directional Sync supports updates made to the following meeting types:

• An individual meeting

• A series of meetings (recurring)

• A single occurrence of a series of meetings

Custom Microsoft Entra application registration is optional

To learn more about setting up a custom application for Zoom Rooms, see the Zoom Support article Setting up Zoom Rooms with Office 365.

Which Zoom endpoints can access calendaring services?

There are four different types of Zoom calendaring endpoints, each of which is covered in more detail later in this document.

• Web Calendaring Service

• Desktop and mobile apps

• Zoom Rooms

• Enhanced API Connector