Auth0 Express Integration

Add authentication to Express.js web applications using express-openid-connect.

Prerequisites

• Express.js application

• Auth0 account and application configured

• If you don't have Auth0 set up yet, use the auth0-quickstart skill first

When NOT to Use

• Single Page Applications - Use auth0-react, auth0-vue, or auth0-angular for client-side auth

• Next.js applications - Use auth0-nextjs skill which handles both client and server

• Mobile applications - Use auth0-react-native for React Native/Expo

• Stateless APIs - Use JWT validation middleware instead of session-based auth

• Microservices - Use JWT validation for service-to-service auth

Quick Start Workflow

1. Install SDK

npm install express-openid-connect dotenv

2. Configure Environment

For automated setup with Auth0 CLI, see Setup Guide for complete scripts.

For manual setup:

Create .env:

SECRET=<openssl-rand-hex-32>

BASE_URL=http://localhost:3000

CLIENT_ID=your-client-id

CLIENT_SECRET=your-client-secret

ISSUER_BASE_URL=https://your-tenant.auth0.com

Generate secret: openssl rand -hex 32

3. Configure Auth Middleware

Update your Express app (app.js or index.js):

require('dotenv').config();

const express = require('express');

const { auth, requiresAuth } = require('express-openid-connect');

const app = express();

// Configure Auth0 middleware

app.use(auth({

  authRequired: false,  // Don't require auth for all routes

  auth0Logout: true,    // Enable logout endpoint

  secret: process.env.SECRET,

  baseURL: process.env.BASE_URL,

  clientID: process.env.CLIENT_ID,

  issuerBaseURL: process.env.ISSUER_BASE_URL,

  clientSecret: process.env.CLIENT_SECRET

}));

app.listen(3000, () => {

  console.log('Server running on http://localhost:3000');

});

This automatically creates:

• /login - Login endpoint

• /logout - Logout endpoint

• /callback - OAuth callback

4. Add Routes

// Public route

app.get('/', (req, res) => {

  res.send(req.oidc.isAuthenticated() ? 'Logged in' : 'Logged out');

});

// Protected route

app.get('/profile', requiresAuth(), (req, res) => {

  res.send(`

    <h1>Profile</h1>

    <p>Name: ${req.oidc.user.name}</p>

    <p>Email: ${req.oidc.user.email}</p>

    <pre>${JSON.stringify(req.oidc.user, null, 2)}</pre>

    <a href="/logout">Logout</a>

  `);

});

// Login/logout links

app.get('/', (req, res) => {

  res.send(`

    ${req.oidc.isAuthenticated() ? `

      <p>Welcome, ${req.oidc.user.name}!</p>

      <a href="/profile">Profile</a>

      <a href="/logout">Logout</a>

    ` : `

      <a href="/login">Login</a>

    `}

  `);

});

5. Test Authentication

Start your server:

node app.js

Visit http://localhost:3000 and test the login flow.

Detailed Documentation

• Setup Guide - Automated setup scripts, environment configuration, Auth0 CLI usage

• Integration Guide - Protected routes, sessions, API integration, error handling

• API Reference - Complete middleware API, configuration options, request properties

Common Mistakes

Mistake

Fix

Forgot to add callback URL in Auth0 Dashboard

Add /callback path to Allowed Callback URLs (e.g., http://localhost:3000/callback)

Missing or weak SECRET

Generate secure secret with openssl rand -hex 32 and store in .env as SECRET

Setting authRequired: true globally

Set to false and use requiresAuth() middleware on specific routes

App created as SPA type in Auth0

Must be Regular Web Application type for server-side auth

Session secret exposed in code

Always use environment variables, never hardcode secrets

Wrong baseURL for production

Update BASE_URL to match your production domain

Not handling logout returnTo

Add your domain to Allowed Logout URLs in Auth0 Dashboard

Related Skills

• auth0-quickstart - Basic Auth0 setup

• auth0-migration - Migrate from another auth provider

• auth0-mfa - Add Multi-Factor Authentication

• auth0-cli - Manage Auth0 resources from the terminal

Quick Reference

Middleware Options:

• authRequired - Require auth for all routes (default: false)

• auth0Logout - Enable /logout endpoint (default: false)

• secret - Session secret (required)

• baseURL - Application URL (required)

• clientID - Auth0 client ID (required)

• issuerBaseURL - Auth0 tenant URL (required)

Request Properties:

• req.oidc.isAuthenticated() - Check if user is logged in

• req.oidc.user - User profile object

• req.oidc.accessToken - Access token for API calls

• req.oidc.idToken - ID token

• req.oidc.refreshToken - Refresh token

Common Use Cases:

• Protected routes → Use requiresAuth() middleware (see Step 4)

• Check auth status → req.oidc.isAuthenticated()

• Get user info → req.oidc.user

• Call APIs → Integration Guide

References

• Express OpenID Connect Documentation

• Auth0 Express Quickstart

• SDK GitHub Repository