Building Scalable Backend Systems with Node.js

Once a niche choice, Node.js now powers high‑throughput APIs at Netflix, Walmart, and PayPal. Its event‑loop model and ubiquitous JavaScript syntax make it ideal for modern micro‑services—if you respect its constraints.

Design Principles for Scale

• Stateless First: Store sessions in Redis, not RAM, so containers can scale horizontally without stickiness.
• Back‑Pressure Aware: Use streams and pipeline() to avoid memory blow‑ups.
• Message‑Driven: Decouple workloads with Kafka or NATS to handle traffic bursts gracefully.

Performance Checklist

• Tune --max_old_space_size for your container footprint.
• Profile hot paths via clinic.js or the Chrome DevTools profiler.
• Isolate CPU‑heavy logic in worker threads or external services.

Combine Node with robust observability, chaos testing, and strict perf budgets, and you’ll comfortably serve millions of RPS.