Single sign-on

What you'll learn

How people sign in to the admin with Google, Microsoft, GitHub or any OpenID Connect provider, who gets in, and how to set up each provider.

Before this page: Users & auth.

Install the providers package and add them to the config:

npm

npm install @easy-cms/auth-oauth

pnpm

pnpm add @easy-cms/auth-oauth

yarn

yarn add @easy-cms/auth-oauth

bun

bun add @easy-cms/auth-oauth

import { github, google, microsoft } from '@easy-cms/auth-oauth'

export default defineConfig({
  serverURL: 'https://cms.example.com', // needed in production, for the callback URL
  auth: {
    providers: [google()], // reads GOOGLE_CLIENT_ID and GOOGLE_CLIENT_SECRET
  },
  // …
})

The login page gets a Sign in with Google button. The provider sends people back to <serverURL>/api/cms/auth/<id>/callback, e.g. https://cms.example.com/api/cms/auth/google/callback: give that URL to the provider (Settings → Single sign-on shows it, with a copy button). Single sign-on is for the admin; your site's visitors are not affected.

Turning providers on adds the user-identities table: create a migration (npx easy-cms migrate:create sso).

Who gets in

• People who already have an account link the provider first: they sign in with their password and choose Link Google (or another provider) on their Account page; the provider's button on the login page doesn't link. After that, the provider's own id for the account is used, so a changed email at the provider doesn't matter. Someone who tries the provider before linking is told to do so.

• Matched by email instead, for a provider whose emails your organization controls (its own Google Workspace or Entra ID): google({ linkByEmail: true }). Only emails the provider has verified count. Site members (auth.members) are always matched by email.

• People from your domains, when you allow it: they get an account the first time they sign in.

  auth: {
    providers: [google()],
    providerSignUp: { domains: ['example.com'], role: 'editor' }, // never 'admin'
  },

• Nobody else: an unknown email lands back on the login page with a message to ask an admin.

• Deactivated users can't sign in, whatever the provider says.

To add someone, create their user in Settings → Users (with their work email) and invite them; they link the provider from their account page, or sign in with it at once with linkByEmail.

Passwords

By default people can sign in either way. To make everyone use the provider:

auth: { providers: [google()], password: false },

Then only admins can still use a password, as a way in when the provider is down; the login page folds the password form away for them. Invitations tell people to sign in with the provider instead of setting a password, and "forgot password" works only for admins.

Linking accounts

On their Account page, people see the outside accounts they sign in with, can link another provider (Link GitHub) and unlink one. The last way into an account can't be unlinked. Admins see and unlink a user's accounts on the user's page. Deleting a user forgets their linked accounts.

Setting up providers

Google

1. In the Google Cloud console, create an OAuth client ID of type Web application. Set up the consent screen first if asked: for a Google Workspace, choose Internal; otherwise External, and while it is in Testing, add the Google accounts that will sign in under Test users (others are refused, and Google warns that the app isn't verified until you publish it).
2. Add the callback URL under Authorized redirect URIs, e.g. https://cms.example.com/api/cms/auth/google/callback (and http://localhost:3000/api/cms/auth/google/callback for development).
3. Set GOOGLE_CLIENT_ID and GOOGLE_CLIENT_SECRET, and use google(). For a Workspace, google({ hd: 'example.com' }) opens the account chooser on your domain.

Microsoft (Entra ID)

1. In the Entra admin center, App registrations → New registration: accounts in this organizational directory only; redirect URI of type Web: https://cms.example.com/api/cms/auth/microsoft/callback.
2. Under Certificates & secrets, create a client secret.
3. Set MICROSOFT_TENANT_ID (the Directory (tenant) ID), MICROSOFT_CLIENT_ID (the Application (client) ID) and MICROSOFT_CLIENT_SECRET, and use microsoft().

Entra ID doesn't mark emails as verified; your organization manages them, so they count as verified. Only the email claim is used, never the user principal name.

GitHub

1. In GitHub, Settings → Developer settings → OAuth Apps → New OAuth App, with the callback URL https://cms.example.com/api/cms/auth/github/callback.
2. Generate a client secret, set GITHUB_CLIENT_ID and GITHUB_CLIENT_SECRET, and use github().

People are matched by the primary, verified email of their GitHub account. For GitHub Enterprise Server: github({ server: { web: 'https://github.example.com', api: 'https://github.example.com/api/v3' } }).

Any OpenID Connect provider

Okta, Keycloak, Auth0, Authentik, Zitadel and others:

import { oidc } from '@easy-cms/auth-oauth'

oidc({
  id: 'okta', // in the callback URL: <api>/auth/okta/callback
  name: 'Okta', // on the button
  issuer: 'https://example.okta.com',
  clientId: process.env.OKTA_CLIENT_ID ?? '',
  clientSecret: process.env.OKTA_CLIENT_SECRET,
})

The provider's /.well-known/openid-configuration is read for its endpoints. Its ID token needs email and email_verified (the email scope).

The id can't be one of the sign-in actions under /auth/ (login, logout, me, init, signup, verify-email, forgot-password, reset-password, first-register) or identities.

How it is kept safe

• The Authorization Code flow with PKCE, a state and (OpenID Connect) a nonce, kept in a short-lived signed cookie; ID tokens are verified with the provider's keys (oauth4webapi).
• After signing in, people only go back to pages of the admin.
• Linking an account needs the session and its CSRF token, and an account already linked to someone else can't be linked again.
• Client secrets stay in environment variables, never in the database or backups.

Next steps

• Roles from the admin: what each person may do once they're in.
• Security: what else is protected.