[ITEM 3] QUESTION: What are Service Workers?

Service Workers are specialized scripts that the browser runs in the background, separately from the web page. They act as a programmable network proxy, intercepting and handling all network requests sent by your web application.

One of the main advantages of this technology is the ability to provide full offline functionality. Thanks to integration with the Cache API, a Service Worker can save HTML pages, styles, scripts, and images locally on the user's device. When the user loses their internet connection, the application still continues to load and work using resources served from the cache.

In addition to caching, Service Workers support background synchronization and Push notifications. Even if the tab with your site is completely closed, the browser can receive a push message from the server, process it using the worker, and show a system notification to the user, which significantly increases audience engagement.

It is important to note the strict security requirements imposed on this technology. Due to their powerful capabilities for intercepting traffic and modifying network responses, Service Workers run exclusively on secure HTTPS protocols (the only exception being local development environments like localhost).

The process of working with them involves registering the script in the main application code, followed by installation and activation stages. During installation, pre-caching of key resources typically occurs, and afterwards the worker intercepts the fetch event, checking for data in the cache before sending a request to the real network.