Concurrency & Multithreading in JavaScript

Abstract

This session was delivered at an internal Amazon web technologies conference in Seattle and focused on concurrency, multithreading, and performance-oriented JavaScript patterns. It was a meaningful milestone personally as well: I was the first Mexican employee from Audible invited to participate in the event. The talk walks through how JavaScript handles work across the event loop and where Web Workers become essential when the main thread starts to bottleneck.

§Topics Covered

• 01How concurrency differs from true multithreading in JavaScript environments
• 02When Web Workers are worth the complexity in real frontend systems
• 03Main-thread bottlenecks, UI responsiveness, and performance tradeoffs
• 04Practical examples for offloading CPU-heavy work from the browser thread
• 05Lessons from presenting JavaScript performance topics in an internal Amazon engineering forum