JavaScript Event Loop Visualizer – Interactive async JavaScript execution insight

Summary: JavaScript Event Loop Visualizer provides real-time, step-by-step visualization of async JavaScript execution, including Call Stack, Web APIs, Task Queue, and Microtask Queue. It supports testing over 12 real-world async patterns or custom code, helping users understand complex async behavior clearly.

What it does

The tool visually demonstrates how JavaScript executes code asynchronously by highlighting the Call Stack, Web APIs, Task Queue, and Microtask Queue in real time. Users can navigate execution steps, adjust speed, and see live code highlighting with plain English explanations for each step.

Who it's for

It is designed for developers learning async JavaScript, preparing for technical interviews, teaching, debugging async issues, and building mental models of event loop behavior.

Why it matters

It makes the invisible async execution process visible, clarifying confusing concepts like Promise prioritization and callback timing, which improves understanding and debugging of async code.