API Authentication

Table of Contents

• Overview
• When to Use
• Quick Start
• Reference Guides
• Best Practices

Overview

Implement comprehensive authentication strategies for APIs including JWT tokens, OAuth 2.0, API keys, and session management with proper security practices.

When to Use

• Securing API endpoints
• Implementing user login/logout flows
• Managing access tokens and refresh tokens
• Integrating OAuth 2.0 providers
• Protecting sensitive data
• Implementing API key authentication

Quick Start

Minimal working example:

// Node.js JWT Implementation
const express = require('express');
const jwt = require('jsonwebtoken');
const bcrypt = require('bcrypt');

const app = express();
const SECRET_KEY = process.env.JWT_SECRET || 'your-secret-key';
const REFRESH_SECRET = process.env.REFRESH_SECRET || 'your-refresh-secret';

// User login endpoint
app.post('/api/auth/login', async (req, res) => {
  try {
    const { email, password } = req.body;

    // Find user in database
    const user = await User.findOne({ email });
    if (!user) {
      return res.status(401).json({ error: 'Invalid credentials' });
    }

    // Verify password
    const isValid = await bcrypt.compare(password, user.password);
    if (!isValid) {
      return res.status(401).json({ error: 'Invalid credentials' });
    }
// ... (see reference guides for full implementation)

Reference Guides

Detailed implementations in the references/ directory:

Guide	Contents
JWT Authentication	JWT Authentication
OAuth 2.0 Implementation	OAuth 2.0 Implementation
API Key Authentication	API Key Authentication
Python Authentication Implementation	Python Authentication Implementation

Best Practices

✅ DO

• Use HTTPS for all authentication
• Store tokens securely (HttpOnly cookies)
• Implement token refresh mechanism
• Set appropriate token expiration times
• Hash and salt passwords
• Use strong secret keys
• Validate tokens on every request
• Implement rate limiting on auth endpoints
• Log authentication attempts
• Rotate secrets regularly

❌ DON'T

• Store passwords in plain text
• Send tokens in URL parameters
• Use weak secret keys
• Store sensitive data in JWT payload
• Ignore token expiration
• Disable HTTPS in production
• Log sensitive tokens
• Reuse API keys across services
• Store credentials in code