Node.js Memory Management and Profiling: Find and Fix Memory Leaks in 2026

Node.js Memory Management and Profiling: Find and Fix Memory Leaks Memory leaks in Node.js servers cause gradual performance degradation and eventual OOM crashes. Unlike garbage-collected languages where leaks "can't happen," V8's garbage collector can't collect objects that are still referenced — even accidentally. Here's how to find and fix them. Understanding Node.js Memory The V8 Heap Structure Node.js Process Memory ├── Heap (V8 managed) │ ├── New Space (Young generation) — small, collected frequently │ ├── Old Space (Old generation) — large, collected less often │ ├── Code Space — JIT-compiled code │ └── Large Object Space — objects > 1MB ├── Stack — call stack, not GC managed ├── External Memory — Buffer (native, outside V8) └── OS Memory — process overhead The Old Space is where memory leaks live. Objects that survive multiple GC cycles get promoted here. V8 only collects them in major GC cycles (expensive) or when heap pressure forces it. Memory Metrics to Watch // Check cu