Shadow DOM
The Shadow DOM is a browser feature that allows developers to create a hidden, encapsulated DOM tree within a normal element. This "shadow" tree's styles and scripts are isolated from the main page. Speed Kit uses this technology to safely pre-render a predicted page in the background. By rendering the page inside a Shadow DOM, it ensures that the pre-rendered page's CSS and JavaScript do not conflict with or disrupt the page the user is currently viewing.
Related web performance terms
- Search Engine Optimization (SEO)
SEO is the process of improving a website's visibility in search engine results pages (like Google). The goal is to rank higher than competitors for relevant search queries to attract more organic (free) traffic.
- Server Response Time
Server Response Time is a component of Time to First Byte that measures how long the server takes to process a request and start sending back a response, excluding network latency.
- Server Timing
Server Timing is a browser API that allows the backend to communicate performance metrics about its own internal processes (e.g., database query time, time to render a component) to the browser via HTTP headers.
- Server-Side A/B Testing
This is a performance-friendly method for running A/B tests. Unlike Client-Side A/B Testing, the decision of which variation to show a user is made on the Origin Server.