What an app can see when you connect your Google or Outlook calendar

The short answer

An app gets the permissions you approve on Google's or Microsoft's consent screen. Google's calendar.events permission lets an app “View and edit events on all your calendars”. Microsoft says Calendars.ReadWrite “allows the app to create, read, update, and delete events in user calendars.” An app can do anything those words cover. Your Google Account and your Microsoft account each list the apps you've approved, and you can remove any of them there.

What does an app get when you connect your calendar?

The app sends you to Google or Microsoft, and they show a consent screen with the app's name and what it wants. Each request comes from a fixed menu of permissions, which Google calls scopes, and each has a description written by Google or Microsoft. The app gets what you approve. Google's help gives the example of an app you authorize to access only your Google Calendar data, which “can only access that data”.

When an app asks Google for more than one permission, Google's developer guide says the consent screen needs individual checkboxes so you can approve or deny each one.

What do Google's calendar permissions allow?

Google offers apps a range of calendar permissions, from read-only to full control. Here are four of them, with Google's own descriptions.

Permission	What Google says it allows
`calendar.events.readonly`	“View events on all your calendars.”
`calendar.events.owned`	“See, create, change, and delete events on Google calendars you own.”
`calendar.events`	“View and edit events on all your calendars.”
`calendar`	“See, edit, share, and permanently delete all the calendars you can access using Google Calendar.”

Of these four, only the broader calendar permission mentions sharing calendars or deleting whole ones, according to Google's list of Calendar scopes.

What does Microsoft's Calendars.ReadWrite allow?

Microsoft labels it “Have full access to user calendars”. Its permissions reference says it “allows the app to create, read, update, and delete events in user calendars.” Microsoft lists it as needing no administrator's consent, and personal Microsoft accounts can grant it. A separate permission, Calendars.ReadWrite.Shared, covers what Microsoft calls “delegate and shared calendars”.

What does TheyCal ask for?

We make TheyCal. When you follow a business with “Continue with Google” or “Continue with Microsoft Outlook”, TheyCal asks for these permissions and no others.

	Google	Microsoft
To sign you in	Your email address and basic profile	`openid`, `email`, `profile`, and `User.Read`: “Sign in and read user profile”
For your calendar	`calendar.events`: “View and edit events on all your calendars”	`Calendars.ReadWrite`: “Have full access to user calendars”
To keep events current after you leave	Offline access	`offline_access`: “Maintain access to data you have given it access to”

Microsoft says offline_access “does not give the app any additional permissions.” It lets the app see and update what you granted while you aren't using it, which is how a business's change reaches your calendar while you're asleep. User.Read also lets an app read basic company information when you sign in with a work or school account.

Google's consent screen for TheyCal, listing the calendar access it asks for with its box unticked — Google's consent screen when you connect TheyCal. The calendar line is the calendar.events permission, and its box starts unticked.

What does TheyCal do with that access?

TheyCal adds the events of businesses you follow to your main calendar. When a business changes or cancels an event, we update or delete that same event, and unfollowing a business takes its upcoming events off. We put no guests on these events. Each one is marked as free time, so a business's event won't make you look busy to anyone checking your schedule.

The permissions would let an app read the rest of your calendar. Each request TheyCal's sync code sends concerns one of the events TheyCal adds, and none of them reads the other events in your calendar.

Google's consent screen lists calendar access with a checkbox of its own. When we connected a test account in October 2026, that box started unticked, so tick it before you press Continue. If you leave it unticked, TheyCal still signs you in, and your Following page shows “No calendar access” until you reconnect and allow it.

How do you see which apps can reach your calendar?

Google. Your Google Account has a linked apps page. Choose Access to your Google Account, select the app, then See details and Remove all access.
Personal Microsoft account, the kind behind Outlook.com. Sign in at accounts.microsoft.com, select Privacy, and on the Overview tab scroll to Apps and services that can access your data. Microsoft's help on disconnecting LinkedIn walks through the same path.
Microsoft work or school account. In the My Apps portal, hover over the app, select its menu, choose Manage your application, then Revoke Permissions. Permissions your administrator granted for you can't be revoked there.
Any work or school account. Your organization has a say too. Google Workspace admins choose which third-party apps can reach the organization's data, and Microsoft lets organizations limit which apps people can approve on their own.

TheyCal's Following page, showing a connected Google calendar marked Adding events, with a Pause button — Your calendars, at the top of TheyCal's Following page.

What happens to events an app already added?

Google says an app whose access you revoke can't reach your data anymore, and that you “may need to contact the developer of the app” to have them delete what they already have.

Once you remove TheyCal's access, it can't reach your calendar to take its events off. If you want those events gone as well, start in TheyCal. Remove the calendar under Connected Accounts in your account settings, and TheyCal takes its upcoming events off that calendar before deleting the connection. After that, remove TheyCal from your Google or Microsoft account. To stop events for a while instead, press Pause on your Following page. Upcoming events come off and past ones stay, and Resume puts them back.

Common questions

Can an app with calendar access read my email?

Google's example is that an app you authorize to access only your Google Calendar data “can only access that data”. Microsoft's description of Calendars.ReadWrite covers events in your calendars, and email doesn't come into it.

Can it see calendars other people share with me?

On Microsoft, a separate permission, Calendars.ReadWrite.Shared, covers “delegate and shared calendars”, and TheyCal doesn't ask for it. Google's wording for calendar.events is “all your calendars”.

How long does an app keep its access?

An app that asked for offline access can keep using your calendar while you aren't using the app. Removing it from your Google Account or Microsoft account ends that.

What if my work account won't let me connect?

Your administrator decides which apps can connect to work accounts, so ask them. On a TheyCal join page you can also pick “Apple Calendar & others” for a private calendar link, which Outlook and Google Calendar can subscribe to without granting TheyCal any access. Our guide to “Add to calendar” buttons and subscriptions explains how those links update.