The App Categories a Shopify App Detector Surfaces
Once you run the detector, the app list groups into the categories that actually shape a store. These are the ones worth reading first:

- Reviews - social-proof apps that put star ratings and photo reviews on product pages.
- Email and SMS - the marketing apps that run abandoned-cart flows, welcome series, and campaigns.
- Upsell and bundles - cart add-ons that raise average order value with offers and product bundles.
- Page builders - the tools behind those custom landing pages and product templates that don't look like the default theme.
- Order tracking - post-purchase tracking pages that cut "where is my order" tickets.
Across the stores Koala tracks, a handful of apps show up again and again in these categories. In Koala's data the most common app is Judge.me Product Reviews, found on 2,187 stores, followed by Klaviyo email and SMS on 1,831 stores, and the PageFly page builder on 770 stores. Read these as the popular default in each category across the stores Koala tracks, not a ranking of all of Shopify. When you see the same names appear on store after store in your niche, you are looking at the stack most sellers have settled on.

Upsell and order-tracking apps round out the picture: cart bundlers and post-purchase tracking pages that don't always show on the surface but shape how much each order is worth and how few support tickets a store fields. The detector names them alongside the reviews, email, and page-builder apps, so you get the whole stack in one list.