The Most Popular Shopify Apps, Ranked by How Many Stores Actually Run Them

The most popular Shopify apps are not the ones with the loudest marketing. They are the ones that quietly show up on store after store because they solve a job every merchant has: reviews, email, support, page building, checkout messaging, analytics, and tracking. Below is a ranking built from Koala's own first-party view across the stores it tracks, grouped by the job each app does, so you can see which tools real merchants keep installing and why.

This is not a paid-placement roundup. The order comes from how many stores actually run each app in our data, which is a very different signal from how prominently an app is advertised. When sellers swap notes on the tools they run to keep a store going, the same categories keep coming up. The numbers below put names and scale to those categories.

A note on the data, up front: these counts reflect the stores Koala tracks, not every store on Shopify, so read them as a strong directional sample rather than a global census. The pattern they show, though, is consistent and useful.

The ranking at a glance

Here is how the most-installed apps stack up across the stores in Koala's data, by number of stores running each one.

App	Job it does	Stores running it
Judge.me Product Reviews	Reviews and social proof	2,407
Klaviyo	Email and SMS	2,003
Shopify Inbox	Customer support and chat	1,105
Klarna On-Site Messaging	Checkout messaging and BNPL	1,012
PageFly	Page building and CRO	866
Loox	Photo reviews and upsell	735
Microsoft Clarity	Store analytics	673
17TRACK	Order tracking	424

The shape of that list is the real lesson. Two jobs, social proof and email, sit at the top by a wide margin, because they map to the two things every store needs: convince a first-time visitor to trust you, then sell to the people who already did. Everything below them is a supporting role.

Reviews and social proof: Judge.me and Loox lead

Reviews are the single most-installed job in our data, and it is not close. Judge.me Product Reviews runs on 2,407 stores, the most of any app we track, and Loox adds another 735 with a more photo-and-video-first take on the same idea.

That dominance makes sense. A cold visitor landing on a product page has one question: does this actually work for people like me. Star ratings and photo reviews answer it on the page, before the visitor has to go looking elsewhere. Judge.me wins on breadth and a generous free tier, which is why it shows up on everything from first stores to large catalogs. Loox leans into visual proof, where customer photos and a review-driven upsell do the persuading.

If you check a strong store in almost any niche, the odds are high it runs one of these two. The takeaway is not "install both." It is that a review system is the closest thing to a non-negotiable in this list, so if you do not have one, that is the first gap to close.

Email and SMS: Klaviyo owns the repeat-sales job

Klaviyo runs on 2,003 stores in our data, second only to reviews. It is the default owned-audience tool for Shopify merchants who are past their first sales and want repeat revenue rather than one-time buyers.

The reason it ranks this high is margin. Paid traffic gets more expensive every year, so the cheapest revenue a store has is the audience it already paid to acquire once. Abandoned-cart, welcome, and win-back flows turn that audience into repeat orders without buying the click again. Sellers obsess over these flows for a reason: a well-built abandoned-cart sequence can recover a meaningful slice of carts that would otherwise vanish, which is exactly why email tools sit so high on the install list.

Klaviyo is the heavyweight choice, and its install count reflects stores that are serious about lifecycle marketing. It is also a clear research signal: when you see it on a competitor, you are looking at a store that invests in keeping customers, not just acquiring them.

Customer support: Shopify Inbox keeps the conversation on-site

Shopify Inbox shows up on 1,105 stores, which puts native customer chat firmly in the must-have tier. It is free, it is built by Shopify, and it lets a store answer pre-sale questions in the moment a visitor is deciding whether to buy.

Its popularity is partly the price and partly the placement. Support apps earn their keep by catching the buyer who has one hesitation left, the question that would otherwise become an abandoned cart. Inbox being first-party and free removes the usual friction of adding a chat tool, so it lands on a huge share of stores by default.

Checkout messaging: Klarna On-Site Messaging sells the payment option

Klarna On-Site Messaging appears on 1,012 stores, and it does a narrower job than the apps above: it tells shoppers, right on the product and cart pages, that they can split the cost or pay later. That is a conversion lever aimed straight at sticker shock on higher-priced carts.

It ranks this high because buy-now-pay-later has become a mainstream expectation, especially for considered purchases. Surfacing the option early, instead of burying it at checkout, nudges the hesitant buyer over the line. When you spot it on a competitor's store, it usually means they sell at price points where financing changes the buy decision.

Page building: PageFly powers custom pages and CRO

PageFly runs on 866 stores, the most-installed page builder in our data. Stores reach for a builder when the default theme stops being enough: custom landing pages for campaigns, richer product pages, and fast variant testing.

A page builder on a store is a tell that the merchant is actively testing offers rather than shipping the theme as-is. PageFly leads here on flexibility and a free plan that lets stores start small. If a competitor in your niche runs it, look at the pages they built with it, because that is where they are experimenting with how to sell.

Store analytics: Microsoft Clarity reads visitor behavior

Microsoft Clarity is installed on 673 stores. It is free, and it gives merchants session recordings and heatmaps so they can see where visitors hesitate, rage-click, or drop off.

Its presence on a store signals an owner who optimizes from evidence instead of hunches. Clarity being free removes the cost barrier that keeps a lot of stores from running behavior analytics at all, which is why it has spread to a meaningful share of the stores we track.

Order tracking: 17TRACK owns the post-purchase moment

17TRACK rounds out the list at 424 stores. It handles the after-the-sale job: branded order tracking and shipment updates that keep the customer informed without flooding your inbox with "where is my order" emails.

It ranks lower than the front-of-funnel apps because tracking is a job stores add once volume makes support tickets painful, not on day one. But for stores shipping real numbers, especially longer-shipping-time models, a tracking app pays for itself in deflected support load.

What this ranking actually tells you

Read the list top to bottom and a strategy falls out of it. The apps that win on installs are the ones that solve a universal job cheaply: proof, repeat sales, support, conversion, testing, insight, and post-purchase. Almost every store needs the top few. Fewer need the bottom few, and they tend to add those later.

That is the opposite of "install everything." The most popular apps are popular because they earn their place, and the strongest stores keep a focused stack rather than a bloated one. Every app you add is a monthly bill and a small tax on your store's speed, so the goal is to fill each job with one lean tool, not to collect tools. For the category-level version of this argument, see our deeper look at what apps top Shopify stores actually run.

The other thing the ranking tells you: a generic best-of list only gets you so far. It tells you which apps are common, not which apps the specific store crushing it in your niche actually chose. For that, you have to look at the store itself.

See the exact app stack of any store you visit

You do not have to guess which of these a competitor runs. Koala Inspector is a free-to-start Chrome extension with a built-in Shopify app detector that reads what a store already loads in your browser and lists the Shopify apps it runs. Open any store, and you can see its real stack in a couple of minutes.

Here is the workflow:

1. Install Koala Inspector from the Chrome Web Store. It runs in your browser, so there is nothing else to set up.
2. Open a store you want to study, a competitor or a brand you admire, on its live site.
3. Click the Koala Inspector icon to load the store's breakdown: theme, estimated traffic, running ads, products, and installed apps.
4. Open the Apps tab to see the exact apps that store runs, so you can match what you find here to a real, working example.
5. Compare a few strong stores in the same niche. When the same app keeps showing up across stores that are clearly doing well, that is a stronger signal than any roundup, including this one.

You learn which category of tool winning stores invest in, you get real app names to evaluate against your own stage and budget, and you avoid buying back the speed problem that comes from copying a whole stack. Want to read a competitor's full setup, not just their apps? See our guide on how to use Koala Inspector.

Install Koala Inspector free and check the first store on your list today.

FAQ

What is the most popular Shopify app?

In Koala's first-party data across the stores it tracks, Judge.me Product Reviews is the most widely installed app, running on more than 2,400 stores. Reviews and email lead the counts because social proof and repeat sales are the two jobs almost every store needs solved before anything else.

Which Shopify apps do most stores actually use?

Most stores fill a short set of jobs rather than one giant app list: a reviews app, an email and SMS tool, a support or chat app, a page builder, a checkout messaging app, store analytics, and order tracking. The popular names that fill those roles in our data include Judge.me, Klaviyo, Shopify Inbox, Klarna On-Site Messaging, PageFly, Loox, Microsoft Clarity, and 17TRACK.

How do I see which apps a specific Shopify store is running?

Open the store in Chrome with the free Koala Inspector extension installed, click the icon, and open the Apps tab. It reads what the store already loads in your browser and lists the Shopify apps it runs, so you can study a competitor's real stack instead of guessing from a generic best-of list.

Should I install all of the most popular apps?

No. The most popular apps are popular because each solves a common job, but every app you add is a recurring cost and a small hit to store speed. Pick the leanest tool for each job you actually have, and add the rest only when your store grows into the need.