- Speed changes behaviour. Google found that as a mobile page's load time goes from one second to three, the chance of a visitor leaving rises by 32%.
- Edge hosting serves your site from a data centre near each visitor instead of from one server far away.
- WebAssembly is excellent for heavy work in the browser, such as editors, 3D and image processing. A typical business site does not need it.
The first version of this article was called "the post-JavaScript era". That was wrong: JavaScript is not going anywhere. What did change is where websites run and how we measure whether they feel fast. This is the practical version.
Why speed is worth paying for
Google's research on mobile landing pages found that as page load time goes from one second to three seconds, the probability of a visitor bouncing increases by 32%. Slow sites lose people before they read a word, and paid ads sending people to a slow page waste money.
Google also uses page experience signals, including Core Web Vitals, in search. A fast site will not rank on speed alone, but a slow one starts behind.
The three numbers to watch
| Measure | What it means | Good |
|---|---|---|
| Largest Contentful Paint (LCP) | How long until the main content appears | 2.5 seconds or less |
| Interaction to Next Paint (INP) | How quickly the page reacts to a tap or click | 200 milliseconds or less |
| Cumulative Layout Shift (CLS) | How much the layout jumps while loading | 0.1 or less |
Google measures these on real visitors' devices and looks at the 75th percentile, so most visitors, not just you on office Wi-Fi, need a good experience. INP replaced an older measure, First Input Delay, in March 2024.
What "the edge" means
A traditional website lives on one server in one city. A visitor on the other side of the world waits for every request to cross oceans. Edge hosting puts your site, and increasingly the code behind it, in data centres in hundreds of cities, so each visitor is served from somewhere close.
ivishwa.com works this way. The pages, the Design Studio and the client portal's backend run on Cloudflare's network, so a visitor in Sydney, Toronto or London is answered from a nearby city, not from Colombo.
What actually makes sites slow
- Huge images. Modern formats such as WebP and AVIF, sized for each screen, fix most of this.
- Too much JavaScript, often from page builders and plugins.
- Third-party scripts: chat widgets, trackers and embedded feeds that load before your content.
- Slow servers far from your visitors.
- Fonts and animation loaded before the text people came to read.
Where WebAssembly fits
WebAssembly lets code written in languages such as C++ or Rust run in the browser at close to native speed. It became a W3C standard in 2019. The best-known example is Figma, which reported that switching to WebAssembly cut its editor's load time by more than three times.
That is the pattern: WebAssembly shines in heavy, app-like work, such as design tools, 3D product configurators, video and image editing in the browser, or complex calculations. A business website that shows pages, takes enquiries and sells products gets its speed from discipline, not from WebAssembly.
How I keep sites fast
- Set a weight budget for each page before design starts.
- Load 3D and rich animation only when it helps, and never before the text.
- Avoid heavy page builders and keep plugins and third-party scripts to a minimum.
- Measure real visitors, not just lab tests. Our analytics records Core Web Vitals from real visits, page by page.
Sources
I design and build websites, online stores and business systems for clients in the US, UK, Europe, Australia and Canada, from Colombo, Sri Lanka. When you work with iVishwa, you talk to me directly, from the first call to launch and after.
Want a straight answer for your own project?
Design your website in the Studio, tell me your budget if you like, and I will reply with one fixed, written quote.
