Enable domain-wide authentication for calendar and file apps in Slack

Who can use this feature?

Workspace owners and workspace admins on the Free, Pro and Business+ subscriptions, and org owners and org admins on Enterprise Grid can automatically connect all their members’ Slack accounts with the Google Calendar, Outlook Calendar or OneDrive and SharePoint app. 

What to expect

  • Any owner or admin can start the domain-wide authentication process.
  • For the Google Calendar or Outlook Calendar app, but you’ll need help from a Google Workspace Super Admin or Office 365 administrator to authorise Slack access from Google Workspace or Office 365. For OneDrive and SharePoint, you’ll need to be an owner or admin in Slack as well as an Office 365 administrator.
  • Once a domain has been verified, the Slack accounts for all members with an email address on that domain will automatically connect to an app.


Step 1: Install a calendar or file app to your workspace

Use the steps in the articles listed below to install the Google Calendar, Outlook Calendar or OneDrive and SharePoint app to your workspace:

If your preferred app is already installed, move on to Step 2.


Step 2: Add a domain

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

Google Calendar

Outlook Calendar

OneDrive and SharePoint

  1. From your desktop, click on  Apps in the left-hand sidebar. If you don't see this option, click  More to find it.
  2. Search for and select Google Calendar. 
  3. From the Home tab, click the Settings button. 
  4. Below Domain-wide authentication, click on Add domain
  5. Enter your company's domain, then click Add
  1. From your desktop, click on  Apps in the left-hand sidebar. If you don't see this option, click  More to find it.
  2. Search for and select Outlook Calendar. 
  3. From the Home tab, click the Settings button. 
  4. Below Domain-wide authentication, click on Add domain
  5. Enter your company's domain, then click Add
To add and verify a domain, the email address on your Slack account needs to match the email address associated with your Office 365 administrator account.
  1. From your desktop, click on  Apps in the left-hand sidebar. If you don’t see this option, click  More to find it.
  2. Search for and select OneDrive and SharePoint.
  3. From the Home tab, click on the Admin settings button.
  4. Below Domain-wide authentication, click on Add domain.
  5. Enter your company’s domain, then click on Add.


Step 3: Grant Slack access from Google Workspace or Office 365 

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

Google Calendar

Outlook Calendar

OneDrive and SharePoint

If you're not a Google Workspace super admin, you'll need someone who is to authorise a domain-wide install for Slack from the Google Workspace Marketplace and verify ownership of your domain.  

Add the Slack app for your domain

  1. From the app's Home tab, click the Settings button. 
  2. Find your domain, then click on the URL in the Domain-wide authentication section. 
  3. When prompted, sign in to your Google Workspace super admin account on the domain you'd like to authenticate. If you're not a Google Workspace super admin, copy the URL and share it with someone who is. Then ask them to follow the remaining steps below. 
  4. Click Domain install
  5. Click on Continue
  6. Tick the box to accept Google's Terms of Service, then select Accept
  7. Click on Done
  8. Return to your workspace and open the Google Calendar app. 


Verify domain ownership

  1. From the app's Home tab, click the Settings button. 
  2. Find your domain, then click on the URL in the Verify domain ownership section. 
  3. When prompted, sign in to your Google Workspace super admin account on the domain you'd like to authenticate. 
  4. Click on Open Slack to return to the Google Calendar app in your workspace.  

If you're not an Office 365 admin, you'll need someone who is to authorise Slack access from Office 365 and verify ownership of your domain. 

Authorise Slack access from Office 365

  1. From the app's Home tab, click the Settings button.
  2. Find your domain, then click on the URL below. 
  3. When prompted, sign in to your Office 365 administrator account on the domain that you'd like to authenticate. If you're not an Office 365 administrator, copy the URL and share it with someone who is. 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 app's Home tab, click the Settings button. 
  2. Find your domain, then click on the URL below to verify ownership of your domain. 
  3. Tick 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. 

Authorise Slack access from Office 365

  1. From the app’s Home tab, click on the Admin settings button.
  2. Find your domain, then click on the URL below.
  3. When prompted, sign in to your Office 365 administrator account on the domain that you’d like to authenticate.
  4. Click on Accept to grant Slack access to your members’ OneDrive and SharePoint accounts.
  5. Click on Open Slack to return to the OneDrive and SharePoint app in your workspace.


Verify domain ownership

  1. From the app’s Home tab, click on the Admin settings button.
  2. Find your domain, then click on the URL below to verify ownership of your domain.
  3. Tick the box to confirm Slack’s access to your members’ OneDrive and SharePoint accounts.
  4. Click on Accept.
  5. Click on Open Slack to return to the OneDrive and SharePoint app in your workspace.

Note: If you’d like to verify more than one domain, a Slack owner or admin who is also an Office 365 administrator with an email address on the domain will need to follow the steps above.


Step 4: Verify your domain

Google Calendar

Outlook Calendar

OneDrive and SharePoint

  1. From the app's Home tab, click the Settings button.
  2. Next to your domain, click on Verify
  3. Enter a valid email address on the domain, then click on Verify

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

  1. From the app's Home tab, click the Settings button.
  2. Next to your domain, click on Verify
  3. Enter a valid email address on the domain, then click on Verify

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

  1. From the app’s Home tab, click on the Admin settings button.
  2. Next to your domain, click on Verify.
  3. Enter a valid email address on the domain, then click on Verify.

Note: If you’re on the Enterprise Grid subscription and installed the OneDrive and SharePoint app at the org level, your domain-wide authentication will apply to all workspaces in your org with access to the app.


Step 5: Choose workspaces in your Enterprise Grid org

After completing the steps above, org owners and admins must select at least one workspace in their org to complete the domain-wide authentication process. 

Google Calendar

Outlook Calendar

OneDrive and SharePoint

  1. From the app's Home tab, click the Settings button.
  2. Below any domain, click Choose to open the drop-down menu.
  3. Scroll to find a workspace, then click on the workspace name to enable domain-wide authentication for that workspace.


Repeat these steps to enable domain-wide authentication for additional workspaces.

  1. From the app's Home tab, click the Settings button.
  2. Below any domain, click Choose to open the drop-down menu. 
  3. Scroll to find a workspace, then click on the workspace name to enable domain-wide authentication for that workspace. 


Repeat these steps to enable domain-wide authentication for additional workspaces. 

If you installed the OneDrive and SharePoint app at the org level, your domain-wide authentications will apply in all workspaces in your org with access to the app. If the app is installed at the workspace level, you’ll need to set up domain-wide authentication from each workspace where you’d like your members’ accounts to automatically be connected to the app.


Manage domains

Note: Any owner or admin can manage domains. Owners and admins 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 or file app in Slack, or need to remove a domain that you’re not using any more, follow the steps below: 

Google Calendar

Outlook Calendar

OneDrive and SharePoint

  1. Open the Google Calendar app in Slack.
  2. From the Home tab, click the Settings button. 
  3. Next to the domain that you want to remove, click on Delete
  4. Then, click Delete to confirm. 
  1. Open the Outlook Calendar app in Slack.
  2. From the Home tab, click the Settings button. 
  3. Next to the domain that you want to remove, click on Delete
  4. Then, click Delete to confirm. 
  1. Open the OneDrive and SharePoint app in Slack.
  2. From the Home tab, click on the Admin settings button.
  3. Next to the domain that you want to remove, click on Delete.

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