Beyond load time
"How fast does it load?" used to be the only performance question worth asking. Perceived performance turns out to be far more nuanced. Google's Core Web Vitals framework gives us a structured way to measure what users actually experience.
The Core Web Vitals
Largest Contentful Paint (LCP)
LCP measures when the largest visible element in the viewport finishes loading. That's usually a hero image, video, or big block of text. It captures the moment a user feels the page is "mostly loaded."
Target: Under 2.5 seconds
How to improve it:
- Optimise and properly size images
- Use modern formats like WebP or AVIF
- Set sensible caching headers
- Preload critical resources
Interaction to Next Paint (INP)
INP replaced First Input Delay (FID). It measures the responsiveness of every interaction throughout a page's lifecycle, not just the first. It captures the worst-case delay between a user action and the visual response.
Target: Under 200 milliseconds
How to improve it:
- Break up long JavaScript tasks
- Push heavy computation to web workers
- Defer non-critical JavaScript
- Tighten event handlers
Cumulative Layout Shift (CLS)
CLS measures visual stability. It quantifies how much the layout shifts unexpectedly as content loads. Nothing annoys a user more than tapping a button and watching the page jump so they hit something else.
Target: Under 0.1
How to improve it:
- Always specify image dimensions
- Reserve space for dynamic content
- Avoid injecting content above existing content
- Use CSS
containfor layout boundaries
Beyond Core Web Vitals
Time to First Byte (TTFB)
How quickly does the server respond? TTFB issues point to server-side problems such as slow database queries, missing caching, or hosting on the wrong continent. For an Australian audience, hosting in a Sydney or Melbourne region usually beats US-East by a clear margin.
First Contentful Paint (FCP)
When does the user first see any content? FCP is the initial sense of progress. A blank white screen feels slow even when the full page lands quickly.
Why this matters for business
Performance isn't just a technical concern. The numbers are consistent: a 1-second delay in page load can cut conversions by 7%, 53% of mobile users abandon sites that take more than 3 seconds, and Google uses Core Web Vitals as a ranking signal.
At CodeDrips, performance is built into the development process from the start, not bolted on at the end. Whether we're building on Gatsby, Next.js, or Shopify, we optimise for these metrics throughout the project.
