Web workers
Workers are secondary processes or threads that execute tasks in the background without blocking the main thread. In the browser (Web Workers API) or server-side (Node.js worker threads, Cloudflare Workers), they parallelize heavy processing to maintain responsiveness.
In practice
On the browser side, a Web Worker can perform intensive computations (CSV file processing, image compression) without freezing the user interface. On the edge, Cloudflare Workers execute JavaScript close to the user with millisecond latency, making them ideal for authentication, personalization, and edge SEO. Not to be confused with Service Workers, which intercept network requests for offline PWA caching.