Frequently Bought Together vs ConvertX: which upsell app fits your Shopify store?

Frequently Bought Together by Code Black Belt has been on the Shopify App Store since March 2017. It does one job: it shows an Amazon-style row of products that pair with the item a shopper is looking at, lets them tick the ones they want and adds the whole set to the cart in one click. In October 2026 its listing shows 1,208 reviews at 4.9 stars and the Built for Shopify badge.

ConvertX arrived in September 2025 with a different idea. Instead of one specialised widget, it puts several conversion tools in one app: quantity bundles, product page upsells, a cart drawer, a sticky add to cart bar, payment icons, shoppable video stories and theme sections. Its upsell module is one piece of that kit. The listing shows 3 reviews at 5.0, which is too few to judge long-term reliability.

So the real question is not "which upsell widget is better", but "do you need a dedicated cross-sell engine, or a lighter upsell inside a broader toolkit?" The answer depends on your catalogue, your order volume and how many other apps you already run. For the general mechanics of the tactic, see our frequently bought together guide.

How each app builds its recommendations

Frequently Bought Together: manual, automatic, global and random

Code Black Belt's help center lists four recommendation sources that feed the widget: manual bundles you build yourself, automatic recommendations, global recommendations that apply across the catalogue, and random fill. Under the default "Standard" algorithm, the app fills every product page with whatever sources you have enabled. A second algorithm, "Exclusive manual bundles", keeps hand-built bundles clean while still letting automatic suggestions cover the rest of the catalogue.

This matters most for stores with hundreds or thousands of SKUs. Nobody wants to hand-pick pairings for 800 products. The developer's Shopify Plus article claims the engine has processed stores with more than 2.6 million orders and 650,000 products, which tells you who it was built for.

The free Starter plan only gives you manual bundles (3 maximum). Automatic and global recommendations start on Professional I.

ConvertX: one offer you pick by hand

ConvertX's upsell module works differently. According to its documentation, you choose the complementary product in the editor, set which products or collections show it, and the offer appears as a compact card above the add to cart button with an image, title, description, price and a checkbox. When the shopper accepts, the extra item goes into the cart together with the main product through the theme's normal add to cart flow.

There is no order-history algorithm listed. That is fine for a shop with 20 products where you already know that the phone case goes with the screen protector. It is a real limitation for a large catalogue, where manual setup does not scale.

Offer formats and discounts

What the widgets look like

Frequently Bought Together shows several products side by side with checkboxes and a total price, the format shoppers know from Amazon. It also displays star ratings pulled from Judge.me, Loox, Yotpo, Stamped.io, Ali Reviews, Opinew or Ryviu, which adds social proof right inside the offer. Each product has a single variant selector listing every combination.

ConvertX shows a single add-on card per offer. Its docs warn against stacking many upsells on one product page, so the intended use is one strong, relevant suggestion rather than a row of three or four. Variant selection inside the card is not listed in its documentation.

Discount types

Here Frequently Bought Together is clearly ahead. Paid plans support four bundle discount types: percentage, fixed amount, cheapest item free and free shipping. You can set them globally or per manual bundle, and set a minimum bundle price.

One caveat comes from Code Black Belt's own help center: when discounts are enabled, the app creates a discount code in your Shopify admin for each bundle added to a cart, and another discount app applied later can replace it. The article recommends the skip-cart redirect and a minimum bundle price to limit abuse. If you run several discount apps at once, read that page before switching it on.

ConvertX's upsell documentation does not list a discount option on the upsell card itself. Discounts in ConvertX live mainly in its Bundles module, which handles quantity offers (buy 2, buy 3) with automatic discounts. Its listing also mentions free gifts on product pages, which Frequently Bought Together only approaches through its "cheapest item free" discount.

Placement and setup

Frequently Bought Together injects itself through an app embed and says it does not modify theme files. You can place the widget on product and cart pages (cart display is listed on paid plans) and even choose different positions on desktop and mobile. Its docs also cover a GemPages integration and a Meta Pixel integration.

ConvertX needs its app embed turned on plus an Upsell app block dragged into the product section of the theme editor. Targeting is broader: the listing says modules can be targeted by product, collection, device or market. Styling covers borders, colours, checkboxes and typography with a live preview.

Both are no-code installs. Frequently Bought Together has more years of theme edge cases behind it, which shows in the size of its knowledge base.

Analytics

Code Black Belt reports rendered, viewed, clicked, added and converted products, conversion percentage and converted amount, all on paid plans. It is detailed for a single widget.

ConvertX tracks clicks, add to cart, checkout and revenue per module. The advantage is that you see the upsell next to your bundles, cart drawer and sticky bar in one dashboard, so you can compare which tool actually brings money.

Pricing: orders versus extra revenue

The two apps bill on different logic, which makes a direct comparison tricky.

Frequently Bought Together charges by order volume: free for up to 3 manual bundles, $9.99/month up to 50 orders, $24.99/month up to 500 orders, $39.99/month above that. Each paid plan has a 14-day free trial.

ConvertX charges by active modules and additional revenue generated: Essential is $19.99/month (or $143.88/year) for up to 4 active modules and up to $1,000 of additional revenue per month, Premium is $34.99/month (or $298.80/year) with no caps. Both include a 7-day trial and 0% commission. There is no free plan, except on development stores.

Three quick scenarios:

• 40 orders a month, upsell only: Frequently Bought Together costs $9.99, or nothing if 3 manual bundles are enough. ConvertX costs $19.99. Frequently Bought Together wins.
• 300 orders a month, upsell plus a cart drawer and a sticky bar: Frequently Bought Together is $24.99 for the upsell alone, and you still need two more apps. ConvertX Essential covers all three for $19.99, as long as the additional revenue stays under $1,000 a month.
• 2,000 orders a month, large catalogue: Frequently Bought Together's $39.99 plan with automatic recommendations is the stronger cross-sell engine. ConvertX Premium at $34.99 makes sense only if you also replace other apps with it.

If you are weighing the cost of stacking apps, our article on free vs paid Shopify apps and the one on app bloat and site speed give useful benchmarks.

Track record and support

This is the widest gap. Frequently Bought Together has nine years on the App Store, 1,208 reviews, a Built for Shopify badge, nine interface languages and priority 24/7 support on paid plans. ConvertX has about a year and 3 reviews. It may well be solid, but there is not enough public feedback yet to prove it, and you should factor that in.

ConvertX's interface is available in English, French, Spanish and German. Frequently Bought Together adds Italian, Dutch, Portuguese (Brazil) and two Chinese variants.

Which store should pick which app

A home goods store with 1,500 SKUs

A shop selling kitchenware with 1,500 products and 1,200 orders a month needs pairings that update on their own. Frequently Bought Together's automatic recommendations, review stars in the widget and four discount types fit this profile. ConvertX's hand-picked upsell would mean hours of setup and would still miss long-tail products.

A skincare brand with 15 products

A small brand with a cleanser, a serum, a cream and a few kits already knows its pairings. It also wants "buy 2, save 10%" offers, a cart drawer with a free shipping bar and a sticky add to cart on mobile. ConvertX covers all of that from one dashboard, and the single upsell card is enough for a catalogue this size. Frequently Bought Together would handle the cross-sell well, but the other three tools would need separate apps.

A new store doing 30 orders a month

On a tight budget, Frequently Bought Together's free plan with 3 manual bundles is hard to beat for testing whether cross-sells work at all. Move to ConvertX later if you want to bundle several conversion tools under one bill.

Moving from one app to the other

From Frequently Bought Together to ConvertX

1. Note your best-performing manual bundles in the Code Black Belt analytics before you uninstall.
2. Install ConvertX, turn on the app embed and add the Upsell app block above the add to cart button.
3. Rebuild your top pairings as upsell offers, targeted by product or collection. Do not try to recreate every automatic recommendation: focus on the 5 to 10 that bring revenue.
4. If you used bundle discounts, check how you will replace them: quantity discounts live in ConvertX Bundles, and a discount on the upsell card itself is not listed.
5. Disable Frequently Bought Together discounts first, then uninstall, and deactivate leftover discount codes in your Shopify admin, as Code Black Belt's help center recommends.

From ConvertX to Frequently Bought Together

1. List the products you targeted with each upsell offer.
2. Install Frequently Bought Together and recreate them as manual bundles (3 on the free plan, unlimited on paid).
3. Turn on automatic recommendations to cover the rest of the catalogue.
4. Remove the ConvertX Upsell app block from the theme so shoppers do not see two offers.
5. Keep ConvertX only if you still use its other modules, like the cart drawer or sticky bar.

For more on where an offer performs best in the journey, read the best time to show an upsell, and for wording, upsell copywriting for Shopify. Merchants comparing broader suites can also look at our Rebuy alternatives and the Bundler vs ConvertX comparison.