Project detail

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Node.js Performance Optimization

A profiling case study that cut request latency from 3.5 seconds to 54 milliseconds by removing event-loop bottlenecks.

RolePerformance engineering and diagnosis

StackNode.js, Worker Threads, Profiling, Load testing

FocusBackend and delivery

Challenge

The system was spending too much time in a CPU-bound path, which made every request feel slow under load.

Solution

I profiled the hot path, moved expensive work off the event loop, and used Worker Threads to keep the API responsive.

Impact

The final result was a 98% latency reduction and a much clearer picture of how to diagnose Node.js performance issues.

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Challenge

The system was spending too much time in a CPU-bound path, which made every request feel slow under load.

Solution

I profiled the hot path, moved expensive work off the event loop, and used Worker Threads to keep the API responsive.

What I Built

Profiling to isolate the slowest parts of the request flow
A CPU-heavy workload moved off the main event loop
Worker Threads to keep the API responsive under pressure
Load testing to compare before and after performance
Documentation of the trade-offs behind the optimization

Impact

The final result was a 98% latency reduction and a much clearer picture of how to diagnose Node.js performance issues.

Why It Matters

This project shows that I can turn a vague slowdown into a measurable engineering improvement.