Short answer
Look at the scripts the storefront loads. Apps that add something to the store, such as reviews, chat, pop-ups or a checkout layer, load scripts from their own addresses, and an app detector reads them and names the apps. Apps that only work in the admin or after the checkout leave no trace, so any list is a minimum.
Free tools for this
What an app detector can see
A store's homepage loads a set of scripts. Many apps add one: a reviews widget, a chat bubble, an email pop-up, a loyalty button, a tracking tag. Each script comes from an address that identifies the app.
A detector reads those addresses, matches them to known apps and groups them. Our free Shopify theme and app detector does this for any store in a few seconds.
How to do it by hand
Open the store and view the page source, or open the browser's developer tools and look at the Network tab with the page reloaded. Filter for scripts and read the addresses.
Scripts from cdn.shopify.com are the store's own theme and Shopify itself. Scripts from other addresses, or from cdn.shopify.com/extensions, usually belong to apps. The app's name is often in the address.
Try it now: Shopify Theme and App Detector → · Shopify App Weight Check →
What you cannot see
Apps that work only in the admin, such as order management, stock sync and shipping tools, add nothing to the storefront. Apps that load only on product, cart or checkout pages will not show up when you read the homepage. Server-side tools are invisible.
So a list of seven apps may be a store running fifteen. Read it as what is visibly there, not everything installed.
How to read the list
Group by job: reviews, chat, search, email, loyalty, checkout, tracking. Two apps doing the same job is the most common sign of waste. Two review apps, or two chat widgets, each load their own scripts on every visit.
A checkout layer such as GoKwik or Shopflo is worth noticing. Third-party checkouts are the most common reason ad platforms stop seeing purchases.
On your own store
Compare what loads with what you think you run. Apps removed from the admin often leave their scripts behind, and visitors keep downloading them. The app weight check goes a step further and shows how many kilobytes each app adds and which ones hold up the page.
On a competitor's store
It is public information, so reading it is fair. Use it to learn what tools successful stores in your niche pick, not to copy a stack. An app that suits a large store with a team can slow a small one.