Shopify App Speed Index

Every Shopify store I audit has the same problem underneath the symptom. The client says mobile conversion is soft, or that Core Web Vitals will not go green. Then I open the app stack and find eleven apps fighting over one main thread.

The tricky part is that no app tells you what it costs you. The listing shows a price and a star rating. It does not show that the review widget you installed for social proof spends a quarter of a second blocking every tap on mobile.

So I built the index I wanted: every major Shopify app, ranked by the blocking time it adds, next to what it charges you for the privilege.

Which Shopify apps slow down your store the most?

Sort the table by blocking time and the shape of the problem is immediate. Page builders sit at the top. Shogun, PageFly and GemPages all clear 240ms because they ship a rendering engine to the browser to do a job that Liquid does on the server for nothing. Review widgets come next, led by Yotpo at roughly 250ms.

The median app in the library costs 90ms. That sounds survivable until you remember these numbers add up. Four median apps and you have burned 360ms of main-thread time before the visitor has done anything at all.

How do I know which of my apps are the problem?

You do not have to guess, and you should not start from this table. Start from your own store:

1. Run the App Bloat Detector on your storefront. It finds which of these 192 apps you actually have.
2. Come back here and sort by blocking time to see which of yours are the expensive ones.
3. Check the “what I would do” column. Where a lighter app does the same job, it is named.
4. Confirm the real-world impact with the CruxGrader, which reads your actual field data from Google.

The order matters. Cutting apps because a table says they are heavy, without knowing what each one earns, is how stores lose revenue while gaining a Lighthouse score.

Is a heavy app always worth removing?

No. This is the part most speed advice gets wrong, and it is worth being blunt about.

An app that earns more than it costs is worth its blocking time. A 120ms email app driving a fifth of your revenue is a good trade. A 250ms review widget doing a job a 40ms one does equally well is not. The question is never whether an app is heavy. It is whether it is heavy for what it does.

That is why the table has a price column. Blocking time and monthly cost are the two things an app takes from you, and you should see them side by side before deciding anything.

The takeaway

• Blocking time, not page weight, is the number that decides whether your store feels fast and whether it passes Core Web Vitals.
• Page builders and review widgets are the heaviest categories, and both have far lighter alternatives.
• The median app costs 90ms, and they stack, so a stack of four average apps is already a problem.
• Only 14 of 192 apps cost more than 180ms each. Find those first.
• Judge every app on what it earns against what it costs, never on the millisecond figure alone.

I am Kaspian Fuad, a Shopify CRO consultant. I built this index from the same library that powers my app detector, and I keep it public because the app listings will never show you this number.