Loop Earplugs: mobile INP about 800 ms faster, checkout conversion +7%
A Shopify store where every click on mobile waited for the template, the apps and the tags. Their developers fixed it, and I showed them where to look.
Loop Earplugs, a Shopify theme with apps on top
Loop sells earplugs online. On mobile, adding to cart and opening the cart drawer took too long to show anything, on the way to the checkout.
Add to cart on mobile: theme code, apps, tags and the cart drawer
We read the INP traces together. The slow clicks were spread over the theme, the apps and the tags, and no single one of them was the cause. Their developers built the fixes; where they needed it, I trained them on reading the traces.
"Mobile got about 800ms faster and checkout conversion went up 7%. It paid for itself pretty much straight away."
Nathan Ziarczyk, Engineering Lead, Loop
Every Shopify app adds a bit to every click
You install an app for one feature, and its script loads on pages and clicks that have nothing to do with that feature. On its own it costs a little. Stacked on a product page with the theme and the tags, it's part of the slow click.
INP is fixed in the template
App settings rarely change what runs in a click. The theme code decides that: what add to cart does, when the cart drawer renders, which app scripts load.
Faster clicks on the way to checkout pay off
I can't promise you 7%. That was Loop's own measurement, on their store.
Slow clicks on your Shopify store on mobile?
One to three days a week, sprint by sprint, working with your developers. From €6,000 a month.
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