Enable domain-wide authentication for calendar apps in Slack

Who can use this feature?
  • Workspace Owners and Workspace Admins
  • FreeStandard, and Plus plans

Workspace Owners and Workspace Admins can automatically connect all of their workspace members' Slack accounts with the Google Calendar or Outlook Calendar app in Slack. 

Note: The ability to enable domain-wide authentication for calendar apps in Slack is rolling out gradually. We appreciate your patience as we make this feature available for all workspaces.

What to expect

  • Any Workspace Owner or Admin can enable domain-wide authentication for a calendar app in Slack, but you'll need a G Suite or Office 365 administrator to authorize Slack access for your organization. 
  • Once a domain is verified, the Slack accounts for all members with an email address on that domain will automatically connect to a calendar app. 
  • If members have disconnected their account from a calendar app in the past, their accounts will automatically reconnect. 
  • Members can change which calendar is connected to Slack or disconnect their calendars at any time. 


Step 1: Install a calendar app to your workspace

Follow the steps below to install the Google Calendar or Outlook Calendar app to your workspace. If a calendar app is already installed, skip ahead to Step 2.

Google Calendar

Outlook Calendar

  1. Visit the Google Calendar page in the Slack App Directory.
  2. Click Add to Slack
  3. Click Allow to grant Google Calendar access to your Slack workspace. 
  4. When prompted, click Open Slack to return to Slack on your desktop. 
  1. Visit the Outlook Calendar page in the Slack App Directory.
  2. Click Add to Slack
  3. Click Allow to grant Outlook Calendar access to your Slack workspace. 
  4. When prompted, click Open Slack to return to Slack on your desktop. 


Step 2: Add a domain

Add your organization's domain to begin the domain-wide authentication process. If members of your workspace have email addresses on more than one domain, repeat the steps below for each domain you'd like to add. 

Google Calendar

Outlook Calendar

  1. From your desktop, click  Apps in the left sidebar. 
  2. Search for and select Google Calendar. 
  3. From the Home tab, click Settings in the top right. 
  4. Below Domain-wide Authentication, click Add domain
  5. Enter your company's domain, then click Add
  1. From your desktop, click  Apps in the left sidebar. 
  2. Search for and select Outlook Calendar. 
  3. From the Home tab, click Settings in the top right. 
  4. Below Domain-wide Authentication, click Add domain
  5. Enter your company's domain, then click Add


Step 3: Grant Slack access from G Suite or Office 365 

After adding a domain, you'll need to grant Slack access to your members' Google Calendar or Outlook Calendar accounts from G Suite or Office 365.

Google Calendar

Outlook Calendar

You need to be a G Suite admin to authorize a domain-wide install for Slack from the G Suite Marketplace and verify ownership of your domain. If you're not a G Suite admin, ask one for help with this step. 

Add the Slack app for your domain

  1. From the Home tab of the Google Calendar app, click Settings in the top right. 
  2. Find your domain, then click the URL in the domain-wide authentication section. 
  3. When prompted, sign in to your G Suite administrator account. If you're not a G Suite administrator, copy the URL and share it with an admin. Then, ask them to follow the remaining steps below. 
  4. Click Domain Install
  5. Click Continue
  6. Check the box to accept Google's Terms of Service, then click Accept
  7. Click Done
  8. Return to your workspace and open the Google Calendar app. 


Verify domain ownership

  1. From the Home tab, click Settings in the top right. 
  2. Find your domain, then click the URL in the verify domain ownership section. 
  3. When prompted, sign in to your G Suite administrator account. 
  4. Click Open Slack to return to the Google Calendar app in your workspace.  

You need to be an Office 365 admin to authorize Slack access from Office 365 and verify ownership of your domain. If you're not an Office 365 admin, ask one for help with this step.

Authorize Slack access from Office 365

  1. From the Home tab of the Outlook Calendar app, click Settings in the top right.
  2. Find your domain, then click the URL below. 
  3. When prompted, sign in to your Office 365 administrator account. If you're not an Office 365 administrator, copy the URL and share it with an admin. Then, ask them to follow the remaining steps below. 
  4. Click Accept to grant Slack access to your members' Outlook Calendar accounts. 
  5. Click Open Slack to return to the Outlook Calendar app in your workspace. 


Verify domain ownership

  1. From the Home tab, click Settings in the top right. 
  2. Find your domain, then click the URL below to verify ownership of your domain. 
  3. Check the box to confirm Slack's access to your members' Outlook Calendar accounts.
  4. Click Accept
  5. Click Open Slack to return to the Outlook Calendar app in your workspace. 


Verify your domain

Google Calendar

Outlook Calendar

  1. From the Home tab of the Google Calendar app, click Settings in the top right.
  2. Next to your domain, click Verify
  3. Enter a valid email address on the domain, then click Verify
  1. From the Home tab of the Outlook Calendar app, click Settings in the top right.
  2. Next to your domain, click Verify
  3. Enter a valid email address on the domain, then click Verify

Note: You'll receive a direct message from the calendar app you've authenticated once all member accounts are connected, which may take up to 24 hours.


Calendar app onboarding for members

If members with email addresses on a verified domain are not already using a calendar app, they'll receive a series of onboarding messages from the Google Calendar or Outlook Calendar app to help them get started:  

  • First, members will be notified that a calendar app is available for them to use in Slack. If they'd like, they can switch the calendar connected to Slack or disconnect their account. Any members who disconnect their account will not receive additional onboarding messages. 
  • Next, members will be prompted to enable status syncing. When status syncing is enabled, the Google Calendar or Outlook Calendar app will automatically set members' Slack statuses reflect that they're in a meeting based on their calendar. 
  • Lastly, members will receive information about tailoring their calendar notification settings in Slack. 


Manage domains

Note: Any Workspace Owner or Admin can manage domains. The owner or admin who added a domain will not be notified if it's removed.

If you no longer want members with email addresses on a certain domain to use a calendar app in Slack, or need to remove a domain you're not using anymore, follow the steps below: 

Google Calendar

Outlook Calendar

  1. Open the Google Calendar app in Slack.
  2. From the Home tab, click Settings in the top right. 
  3. Next to the domain you'd like to remove, click Delete
  4. Then, click Delete to confirm. 
  1. Open the Outlook Calendar app in Slack.
  2. From the Home tab, click Settings in the top right. 
  3. Next to the domain you'd like to remove, click Delete
  4. Then, click Delete to confirm. 

Tip: To uninstall a calendar app from Slack, follow the steps in Remove apps and custom integrations from your workspace.