First Contentful Paint

Definitions

1. A performance metric measuring the time from navigation to when the browser renders the first piece of DOM content (text, image, canvas). Signals to users that the page is loading. Good: < 1.8s, Needs improvement: 1.8-3s, Poor: > 3s. Improved by reducing server response time, eliminating render-blocking resources, and using critical CSS.

   In plain English: How long it takes for the first thing to appear on screen when loading a web page.

   Example: "FCP is 3.2 seconds because the 500KB JavaScript bundle blocks rendering — inline the critical CSS and defer the JS."

Related Terms

• Allocator
• Big-O
• Cache
• Core Web Vitals
• Cumulative Layout Shift
• Largest Contentful Paint
• Token Per Second
• Lighthouse Score Obsession