auth0-express

SKILL.md

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