Simplify Your Stack (and Save!): A Guide to Linking Your Auth0 Tenants

Linking Auth0 tenants allows you to manage multiple Auth0 instances as a single entity, simplifying configuration and management. This is particularly useful for organizations with multiple business units, regions, or products that require separate Auth0 instances but need unified management.

What is linking Auth0 tenants?

Linking Auth0 tenants involves setting up cross-tenant connections so that you can manage authentication and authorization across multiple Auth0 instances. This setup helps streamline operations, reduce redundancy, and improve security consistency across your organization.

Why link Auth0 tenants?

Using a single management console for multiple Auth0 tenants can significantly reduce administrative overhead. It also ensures that security policies and configurations are consistently applied across all instances, reducing the risk of misconfigurations.

How do you set up linking between Auth0 tenants?

Setting up linking between Auth0 tenants involves several steps, including creating custom rules and configuring cross-tenant connections.

Step-by-step guide to linking Auth0 tenants

Configure a Custom Database Connection

First, you need to set up a custom database connection in one of your Auth0 tenants. This connection will act as the primary source of truth for user data.

function login(email, password, callback) {
  // Connect to your database and validate the user
  const user = findUserByEmail(email);
  if (!user || !comparePassword(password, user.password)) {
    return callback(new WrongUsernameOrPasswordError(email));
  }
  callback(null, {
    user_id: user.id.toString(),
    nickname: user.nickname,
    email: user.email
  });
}

Set Up Rules for Cross-Tenant Authentication

Next, create rules in each tenant to handle authentication requests and redirect them to the primary tenant for validation.

function (user, context, callback) {
  if (context.clientName === 'Secondary Tenant') {
    const targetTenantDomain = 'primary-tenant.auth0.com';
    const redirectUrl = `https://${targetTenantDomain}/login?connection=your-custom-db&client=${context.clientID}&redirect_uri=${encodeURIComponent(context.protocol + '://' + context.request.hostname + '/login/callback')}&state=${context.request.query.state}`;
    return callback(null, user, { redirect: redirectUrl });
  }
  callback(null, user, context);
}

Secure Cross-Tenant Communication

Ensure that communication between tenants is secure by using HTTPS and validating tokens.

function (user, context, callback) {
  const jwt = require('jsonwebtoken');
  const jwksClient = require('jwks-rsa');

  const client = jwksClient({
    jwksUri: 'https://primary-tenant.auth0.com/.well-known/jwks.json'
  });

  function getKey(header, callback){
    client.getSigningKey(header.kid, function(err, key) {
      const signingKey = key.publicKey || key.rsaPublicKey;
      callback(null, signingKey);
    });
  }

  jwt.verify(user.idToken, getKey, {}, function(err, decoded) {
    if (err) {
      return callback(new Error('Invalid token'));
    }
    callback(null, user, context);
  });
}

Security considerations

Ensure proper access controls

Implement strict access controls to prevent unauthorized access to tenant configurations and user data.

Encrypt sensitive data

Always encrypt sensitive data, such as passwords and tokens, both in transit and at rest.

Regularly audit configurations

Regularly audit your Auth0 tenant configurations to ensure they meet security standards and detect any anomalies.

Best practices

Use environment variables

Store configuration settings, such as client IDs and secrets, in environment variables to keep your codebase clean and secure.

Implement logging and monitoring

Enable logging and monitoring to track authentication requests and detect suspicious activities.

Keep software updated

Regularly update your Auth0 tenants and any related software to patch vulnerabilities and improve security.

Comparison of different approaches

Quick reference

Troubleshooting common issues

Error: Invalid token signature

Solution: Ensure that the JWKS URI is correct and that the token is signed with the correct key.

Error: User not found

Solution: Verify that the user exists in the primary tenant’s database and that the database connection is correctly configured.

Key takeaways

This setup saved me 3 hours last week by eliminating redundant configurations across multiple tenants. Give it a try and streamline your identity management stack today.