Building Scalable APIs with Node.js

# Building Scalable APIs with Node.js Creating APIs that scale is both an art and a science. Let's explore the key principles. ## Architecture Principles ### 1. Stateless Design Keep your API stateless to enable horizontal scaling: ```javascript // Bad - stateful let userSession = {}; // Good - stateless app.get('/user', authenticateToken, async (req, res) => { const user = await getUserFromToken(req.token); res.json(user); }); ``` ### 2. Rate Limiting Protect your API from abuse: ```javascript const rateLimit = require('express-rate-limit'); const limiter = rateLimit({ windowMs: 15 * 60 * 1000, max: 100 }); app.use('/api/', limiter); ``` ## Database Optimization - Use connection pooling - Implement proper indexing - Cache frequently accessed data ## Monitoring Always monitor your API's performance and errors. Tools like: - Prometheus - Grafana - DataDog ## Conclusion Scalability is a journey, not a destination. Keep iterating and improving!