Blocking CSS/JS Requests
Blocking (or render-blocking) requests are requests for CSS or JavaScript files that the browser must download, parse, and execute before it can continue rendering the rest of the page. These resources are a major cause of slow load times because they block the Main Thread and delay the First Contentful Paint. A key performance strategy is to eliminate or minimize blocking requests.
Related web performance terms
- Back/Forward Cache (bfcache)
The back/forward cache (or bfcache) is a browser optimization that enables instant navigations when a user clicks the back or forward buttons.
- Backend
The backend refers to the server-side components of a web application that are not visible to the end-user. This includes the web server, application logic, and databases.
- Backend Cache (AWS)
This is Speed Kit's central, primary cache where Anonymous HTML and other website assets are stored. It is hosted on Amazon Web Services (AWS), a secure and highly reliable cloud computing platform.
- Backend Time
Backend Time is the duration it takes for a website's Origin Server to process a request and generate the HTML for a page.