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Slack#

Lets people sign in with their Slack account, through Sign in with Slack (OpenID Connect). Last checked against Slack's documentation on 31 October 2026.

Set it up#

  1. Run leptoskit auth provider add slack. It adds:

    [auth.providers.slack]
client_id_env = "SLACK_CLIENT_ID"
client_secret_env = "SLACK_CLIENT_SECRET"

  2. In Slack's app settings, create an app, and under OAuth & Permissions add the user scopes openid, email, and profile.

  3. Add the Redirect URLs https://myapp.com/auth/callback/slack, and http://localhost:3000/auth/callback/slack for development.

  4. Set SLACK_CLIENT_ID and SLACK_CLIENT_SECRET.

  5. Turn on the auth-providers feature, and run leptoskit auth doctor.

What sign-in gets#

Slack's ID token: the person's user ID, their workspace, their name and picture, and their email address with Slack's email_verified flag.

A Slack account belongs to one workspace, so leptoskit identifies the person by the workspace and the user together. Someone who signs in from two workspaces has two connected accounts, which they can connect or merge into one account themselves.

Platforms#

It works on the web, and in iOS, macOS, and Android apps through the system browser, with the same redirect URIs: the browser comes back to your site, which sends it on to the app. See Sign-in for each platform.

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