Your website is slow: what to check in 15 minutes

Published 2026-11-03 · 7 min read · By the Alian Digital team

A slow site loses visitors and search positions. The good news: in most cases the cause is one of a few typical ones and you can check them in a quarter of an hour.

1. Measure, do not guess

Run Google PageSpeed Insights or Lighthouse in Chrome DevTools for the home page and one inner page. Look at the mobile results, because they are usually worse. Google considers these values "good": largest element (LCP) within 2.5 s, response to input (INP) within 200 ms, layout shift (CLS) within 0.1.

2. Images

• Serve modern formats (WebP or AVIF) instead of heavy JPG and PNG.
• Do not upload a 4000 px image if the page needs 800.
• Lazy-load images below the first screen, but not the main one.
• Set width and height so the layout does not jump.

3. Fonts

Host fonts on your own server, include only the weights and languages you need and add font-display: swap. Loading ten weights from someone else's server easily adds half a second.

4. Scripts and widgets

Analytics, chats, pixels, maps, sliders: each adds code and requests. Remove what you do not use and load the rest after the first user interaction.

5. Hosting, cache and CDN

A slow server response (TTFB) is not cured by optimising images. Check the plan, turn on caching and consider a CDN. For static sites this is especially simple.

6. Plugins and theme (WordPress and similar)

Every plugin adds requests and code. Disable the unneeded ones, update the rest and replace a heavy theme with a lighter one. Check that several optimiser plugins are not fighting each other.

7. The hero banner and slider

A big slider on the first screen is often the very "largest element" that hurts LCP. Replace it with one optimised image or text.