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What is JS Visualizer?
Watch JavaScript execute step by step. See the call stack, Web APIs, microtask & task queues, and event loop animate in real time. Finally understand why Promises fire before setTimeout and how async/await actually works. ✦ Breakpoints, step mode, speed control ✦ 20+ examples · Side-by-side comparison · Share via URL ✦ Spec-linked step explanations Free. No signup.
