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Website performance audit: 12 checks

The checks we run to make sites fast - do them yourself.

A slow site quietly costs you customers and rankings - every extra second of load time measurably reduces conversions, and mobile visitors are the least patient of all. Here are twelve checks we run when we audit a site for speed. Most are things you can look at yourself today.

The 12 checks
  • Run a speed test (like PageSpeed Insights) and note your mobile score
  • Compress and correctly size every image - this is the most common culprit
  • Serve modern image formats and lazy-load anything below the fold
  • Remove unused apps, plugins, and third-party scripts you don't need
  • Defer or minify heavy JavaScript and CSS
  • Make sure your largest content paints in under ~2.5 seconds on mobile
  • Use a CDN so assets load from close to your visitors
  • Enable browser caching for static files
  • Check your hosting - cheap, overloaded hosting caps everything else
  • Audit fonts: limit weights and load them efficiently
  • Test on a real phone on a normal connection, not just office wifi
  • Re-test after each change so you know what actually helped

How to prioritise

If you only do three things, do these: compress your images, cut the scripts and apps you don't use, and make sure your hosting isn't the bottleneck. Those three fix the majority of slow sites.

What "good" looks like

Aim to pass Core Web Vitals on mobile, with pages that feel instant to a real user. Speed isn't a one-off project - it creeps back as you add content and tools, so re-audit a couple of times a year. If your scores won't budge, we're happy to take a look and find the specific fixes that will move them.

More resources

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