Critical Rendering Path
The critical rendering path is the sequence of steps a browser must take to process the HTML, CSS, and JavaScript files required to render the initial, above the fold view of a webpage. Optimizing this path involves minimizing the number and size of these "render-blocking" resources to allow the browser to paint content to the screen as quickly as possible. A long or bloated critical rendering path is a common cause of a slow First Contentful Paint (FCP).
Related web performance terms
- CDN (Content Delivery Network)
A CDN, or Content Delivery Network, is a globally distributed network of servers designed to deliver web content to users quickly and efficiently.
- CORS (Cross-Origin Resource Sharing)
CORS is a browser security feature that uses HTTP headers to manage whether a web page from one domain is allowed to fetch resources from another domain.
- CPU time
CPU time is the amount of time the Central Processing Unit (CPU) of a user's device spends processing the scripts and rendering a webpage.
- Cache
A cache is a high-speed, temporary storage layer designed to store copies of website files (like HTML, images, and scripts) closer to the user.