OAuth Implementation

Table of Contents

• [Overview](#overview)
• [When to Use](#when-to-use)
• [Quick Start](#quick-start)
• [Reference Guides](#reference-guides)
• [Best Practices](#best-practices)

Overview

Implement industry-standard OAuth 2.0 and OpenID Connect authentication flows with JWT tokens, refresh tokens, and secure session management.

When to Use

• User authentication systems
• Third-party API integration
• Single Sign-On (SSO) implementation
• Mobile app authentication
• Microservices security
• Social login integration

Quick Start

Minimal working example:

// oauth-server.js - Complete OAuth 2.0 implementation
const express = require("express");
const jwt = require("jsonwebtoken");
const crypto = require("crypto");
const bcrypt = require("bcrypt");

class OAuthServer {
  constructor() {
    this.app = express();
    this.clients = new Map();
    this.authorizationCodes = new Map();
    this.refreshTokens = new Map();
    this.accessTokens = new Map();

    // JWT signing keys
    this.privateKey = process.env.JWT_PRIVATE_KEY;
    this.publicKey = process.env.JWT_PUBLIC_KEY;

    this.setupRoutes();
  }

  // Register OAuth client
  registerClient(clientId, clientSecret, redirectUris) {
    this.clients.set(clientId, {
      clientSecret: bcrypt.hashSync(clientSecret, 10),
// ... (see reference guides for full implementation)

Reference Guides

Detailed implementations in the references/ directory:

Best Practices

✅ DO

• Use PKCE for public clients
• Implement token rotation
• Store tokens securely
• Use HTTPS everywhere
• Validate redirect URIs
• Implement rate limiting
• Use short-lived access tokens
• Log authentication events

❌ DON'T

• Store tokens in localStorage
• Use implicit flow
• Skip state parameter
• Expose client secrets
• Allow open redirects
• Use weak signing keys