hardSystem Design

What are some common ways to improve performance in a Node.js application?

Q: What are some common ways to improve performance in a Node.js application?

**TL;DR.** Keep the **event loop unblocked** (no sync CPU work in handlers — offload to workers), do I/O **concurrently** ( Promise.all , connection pools, keep-alive), add **caching**, **stream** large payloads, **scale across cores** (cluster/replicas), and **measure first** (profiling) so you optimize the real bottleneck. unblock loop workers async I/O concurrency Promise.all <text class='d-sub' x='

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This question evaluates understanding of optimization techniques specific to Node.js applications.

performanceoptimizationcachingscalability

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Two quick wins

// ❌ serial I/O
const a = await getA(); const b = await getB();
// ✅ concurrent
const [a2, b2] = await Promise.all([getA(), getB()]);

// ❌ blocks the loop for every request
const hash = crypto.pbkdf2Sync(pw, salt, 1e6, 64, 'sha512');
// ✅ async → off the main thread
const hash2 = await pbkdf2Async(pw, salt, 1e6, 64, 'sha512');

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