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GC Visualizer - Free Online JavaScript Memory Tool | IconVault

Watch garbage collection animate: young-generation scavenge, old-generation mark-sweep, plus common leak patterns. Free in your browser.

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GC Visualizer

Watch scavenge and mark-sweep passes reclaim memory

5 of 5 free uses left

Watch a young-generation scavenge copy live objects to survivor space, then see a leaked global survive the next full collection.

YOUNG GENERATION (EDEN)SURVIVOROLD GENwindowrootstack framerootcacheyounguseryoungcartyoungtmp datayoungclosed modalyoungsettingsold

Frame 1 of 7: Allocate

8 objects on the heap

Your app allocates objects in the young generation (Eden). window and the stack frame are roots: everything the collector can reach from a root survives.

5 of 5 free runs left. Stepping through frames manually is always free.

Heap size across collections

8
8
7
9
9
8
8

Objects on the heap after each collection. A healthy heap returns to baseline; a leaking one climbs.

Object inspector

Click any object on the heap to inspect its references.

Simplified model

Real engines use generational collectors with write barriers, incremental and parallel marking, and concurrent sweeping. Object sizes, timings and heap layouts here are illustrative, but the core rule is exact: if a root can reach it, the collector keeps it.

About this tool

IconVault's GC Visualizer animates how a generational garbage collector works: watch the young generation get cleaned by scavenge passes, survivors get promoted to the old generation, and long-lived objects get swept by mark-sweep. Roots stay pinned while unreachable objects fade away.

It also demonstrates classic memory leak patterns (detached listeners, growing caches, accidental globals) with tips for fixing each. Built for students and developers who want to understand V8's memory model. Free and runs fully in your browser.

Frequently asked questions

Popular searches

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