Speed is not a technical detail
A slow site loses people before they see anything. They do not complain. They just leave, and you never find out they were there.
It affects search ranking too. But ranking is the smaller cost. The real one is the person who never saw your work.
Test it properly first
Do not guess. Open your site on a phone, on mobile data, not on office wifi. That is the honest test.
Then run it through a free speed tool and read the phone number, not the desktop one. Most people check desktop, feel fine, and never see the result their customers actually get.
Cause one: images
This is the big one. Nine times out of ten, it is images.
Someone uploads a photo straight off a camera. It is 4,000 pixels wide and four megabytes. It displays at 600 pixels. The browser downloads all four megabytes anyway.
The fix is boring and it works.
- Resize images to the size they actually display at, doubled for sharp screens.
- Use a modern format. WebP is fine and widely supported.
- Give every image a width and height so the page stops jumping as it loads.
- Load images below the fold only when someone scrolls to them.
Cause two: fonts
Every web font is a file somebody has to download before your text shows up.
Three families with four weights each is twelve files. We have seen sites do this without anyone noticing.
Pick two families. Pick the weights you actually use. Two families with two weights each is four files, and almost nobody can tell the difference.
Cause three: other people’s scripts
Analytics, chat widgets, heat maps, testing tools, embedded video, social buttons. Each one is a script from somebody else’s server.
Every one is a request you do not control, running while your page is trying to finish.
Go and list what is on your site right now. We usually find at least one thing nobody remembers adding, still loading on every page, for everyone.
What to do this week
- Test on a phone, on mobile data.
- Find your three biggest images and shrink them.
- Count your fonts. Cut back to two families.
- List your third-party scripts and remove any nobody can justify.
That is an afternoon of work and it usually fixes most of it. The deeper engineering only matters after you have done the boring part.
When it really is the code
Sometimes it is. Heavy frameworks, too much JavaScript, a slow server.
But we would not start there. We have audited a lot of slow sites, and images were the main cause in most of them. Start cheap.
Worth remembering
In four lines
- Test on a phone using mobile data, not office wifi.
- Images are the cause most of the time.
- Two font families is plenty. Twelve files is not.
- List your third-party scripts and delete what nobody can name a reason for.
Questions we get asked
What speed score should we aim for?
Do not chase a perfect score. Aim for the page feeling usable in about two seconds on a mid-range phone. That matters more than the number in the tool.
Do we need a rebuild to get faster?
Usually not. Images, fonts and scripts are content and configuration problems. You can fix most of it without touching the build.
Does speed really affect ranking?
It is one signal among many. Do not fix speed for the ranking. Fix it because people leave.
Read next
Working on this yourself?
We help teams sort this out for a living. Tell us what you’re building, or see how it went for other people.