The sale that almost happened
A shopper decides in seconds, and most of that decision happens after the add to cart. The checkout is where a fast site so often goes to die, because this is the one page that runs against the clock while cards are already out. Two or three sluggish spots here do not just frustrate people, they refund the effort of every campaign that brought them. Here is the fifteen-minute audit, and each slow spot comes with its fix.
You will need your store open in a browser and the developer tools, usually a right-click then Inspect, with the Network tab selected. Set the throttle to Fast 3G and walk through your own checkout exactly as a customer would. That throttled view is closer to the mobile high street than your office wifi will ever be.
Slow spot 1: The product page image party
Watch the first few requests after you open a product page. Oversized hero images loading at full original resolution are the most common tax, and they land before a shopper has read a word. If an image is bigger than the screen it appears on, the server is winning and the customer is losing.
The fix, in order: compress and resize images to their display size, serve them in WebP where your platform allows it, enable lazy loading for anything below the fold, and let your platform or a well-reviewed image app handle the conversion. The page should visually settle within a couple of seconds on that throttled connection.
Slow spot 2: The app you forgot you installed
Every app, widget, and tracking snippet adds requests to the most expensive page in your store. In the Network tab the names scroll past, and each one is a small toll gate on the way to your buy button. Apps installed for one campaign in March and never removed are still collecting that toll every day.
The fix: open your installed apps list and be ruthless. Anything not actively earning its place goes. Then re-test the checkout and watch the number of requests drop. Where your platform allows it, check for a built-in alternative to a paid app, because native features load faster than bolted-on ones.
Slow spot 3: The third-party scripts that block the button
Some scripts cannot be avoided, chat widgets and payment tools among them, but how they load changes everything. A script that blocks rendering holds the whole page hostage, and the buy button, the only thing that matters, waits politely behind it.
The fix: make non-essential scripts load late rather than first. In practice that means deferring what you can, keeping the payment step lean, and resisting the urge to add one more embed. If you work with a developer, the one-line ask is simple: audit and defer non-critical third-party scripts on checkout-adjacent pages.
Then measure like a shopkeeper, not like an engineer
PageSpeed Insights on your product page and checkout will give you a score, but the storekeeper’s measure is simpler: on a throttled connection, how long until a shopper can see the price, and how long until they can press buy. Shorten those two gaps and you have done more for December revenue than any clever campaign tweak this month.
Run the audit once now, and once after you install anything new, because checkouts only stay fast when someone occasionally looks.
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