Slack cloud application

You must be signed in as a super administrator for this task.

With Security Assertion Markup Language (SAML), your users can sign in to enterprise cloud applications with their Google Cloud credentials.

Set up SSO via SAML for Slack

Step 1: Set up Google as a SAML identity provider (IdP)
  1. Sign in to your Google Admin console.

    Sign in using an account with super administrator privileges (does not end in

  2. From the Admin console Home page, go to Appsand thenSAML apps.
  3. Click Add  at the bottom right.
  4. Locate and click Slack in the application list.
  5. On the Google IDP Information page, download the IDP metadata and copy the SSO URL and EntityID.
  6. Click Next.

    The Basic information window shows the Application name and Description seen by users.

  7. Click Next.
  8. On the Service Provider Details page, enter the following:
    • ACS URL:
    • Entity ID:
    • Start URL: Leave empty 

      Note: The same Entity ID can't be used by more than one SAML app. So, if the Entity ID has already been used by another Slack SAML app, set the Entity ID to instead.
  9. Check the Signed Response box.
  10. (Optional) Change the default Name ID as needed. You can use user schema custom attributes after creating them via Google Admin SDK APIs, but you have to create custom attributes before setting up the Slack SAML app. Name ID can have one value.
  11. Set Name ID Format to Persistent.
  12. Click Next.
  13. On the Attribute Mapping page, set the User.Email category to Basic Information and the user field to Primary Email.
  14. (Optional) Add name attributes. Google can use name attributes to pass information to the Slack app during user authentication.
    1. In both cases, set the category to Basic Information.
    2. For the first name, set the user field to First Name.
    3. For the last name, set the user field to Last Name
  15. Click Finish.
  16. In the Setting up SSO for Slack window, click OK. You need to set up SSO before setting up auto-provisioning.
Step 2: Enable the Slack SAML app

It can take up to 24 hours for this change to propagate to all users.

  1. Sign in to your Google Admin console.

    Sign in using your administrator account (does not end in

  2. From the Admin console Home page, go to Appsand thenSAML apps.
  3. Select Slack.
  4. Click User access.
  5. To turn on or off a service for everyone in your organization, click On for everyone or Off for everyone, and then click Save.

  6. To turn on or off a service only for users in an organizational unit:

    1. At the left, select the organizational unit.
    2. Select On or Off.
    3. To keep the service turned on or off even when the service is turned on or off for the parent organizational unit, click Override.
    4. If the organization's status is already Overridden, choose an option:
      • Inherit—Reverts to the same setting as its parent.
      • Save—Saves your new setting (even if the parent setting changes).

    Learn more about organizational structure.

  7. (Optional) Turn on the service for a group of users.
    Use access groups to turn on a service for specific users within or across your organizational units. Learn more

  8. Ensure that your Slack user account email IDs match those in your Google domain.
Step 3: Set up Slack as a SAML 2.0 service provider (SP)
  1. Sign in to Slack at with your organization's slack team owner or administrator account.
  2. Click Settings & Permissions.
  3. Click the Authentication tab.
  4. Next to SAML authentication, click Configure.
  5. Confirm your password.
  6. In the Choose your SAML provider window, select Custom SAML 2.0 and then click Configure.
  7. In the SAML 2.0 Endpoint (HTTP) field, paste the the SSO URL you copied in step 1.
  8. In the Identity Provider Issuer field, paste the the Entity ID you copied in step 1.
  9. In the Public Certificate field, paste the entire contents of the file you downloaded in step 1. This is an X.509 Certificate that’s required for SSO setup. You might need to rename the file extension to “.txt” so you can open the file with a text editor.
  10. If you set the Entity ID in your Slack SAML app to something other than, click Advanced Options and paste the Entity ID value into the Service Provider Issuer field.
  11. Under Settings, indicate how authentication should be applied to your team.
  12. Click Save Configuration.
Step 4: Verify that the SSO is working

Slack supports both Identity Provider (IdP) initiated and Service Provider (SP) initiated SSO. Follow these steps to verify SSO in either mode:


  1. Sign in to your Google Admin console.

    Sign in using your administrator account (does not end in

  2. From the Admin console Home page, go to Appsand thenSAML apps.
  3. Select Slack.
  4. At the top left, click Test SAML login

    Slack should open in a separate tab. If it doesn’t, use the information in the resulting SAML error messages to update your IdP and SP settings as needed, then retest SAML login.


  1. Close all browser windows.
  2. Open and attempt to sign in with SAML. You should be redirected to the Google sign-in page.
  3. Enter your user name and password.

After your credentials are authenticated, you are redirected back to Slack.

Step 5: Set up auto-provisioning

As a super administrator, you can automatically provision users in the Slack application.

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