Show what customers really buy together, with the combined price and one Add all to cart button.
Available Updated Oct 17, 2026Version 1.0.0CS-Cart, Multi-Vendor 4.17.2 – 4.21.x No core file edits
Built for
Frequently Bought Together & Cross-sell: overview1 of 14
What it does
Frequently Bought Together & Cross-sell finds the products your customers buy in the same order and shows them on the product page: the product plus up to three companions, checkboxes, the combined price and one Add all to cart button. A second block suggests products for the items in the cart. Nothing to build by hand: the sets come from your completed orders and update every day. For any CS-Cart or Multi-Vendor store with accessories, consumables or matching items.
How it works
After installation the add-on analyses your orders: pairs of products in the same order, with recent orders weighing more, a minimum number of orders and a minimum confidence. A daily cron job keeps the data fresh. Until enough orders exist, popular products of the same category fill the block. Pin or exclude products on the product's Bought together tab, add a cart promotion with the Frequently bought together discount bonus if you like, and follow the results under Marketing. In Multi-Vendor, products are recommended within the same vendor.
Features
Recommendations computed automatically from completed orders
Order statuses, history window, recency weighting, support and confidence settings
Product page block with checkboxes, combined price and Add all to cart
Cart page block with one-click Add to cart
Only products that can be bought right away are shown
Pinned and excluded products, hide the block per product
Category fallback for new stores and new products
Bundle discount as a CS-Cart promotion bonus, savings shown in the block
Multi-Vendor: same-vendor recommendations, vendor pins; CS-Cart Ultimate: per storefront
CS-Cart, CS-Cart Ultimate and Multi-Vendor, 4.17.2 to 4.21
What you get
Package
kv_frequently_bought_together-1.0.0.zip, installed through Add-ons → Manage add-ons
Updates & support
12 months included. Download new versions from your account and install them in Add-ons → Manage add-ons or the Upgrade Center.
License
1 production installation. Staging, dev and localhost are free and unlimited. The add-on keeps working after the update period ends. How licensing works
Compatibility
We list only the builds we install and test on. “Tested” means the full test plan was run on that build; “Supported” means the build is inside the supported range and uses the same hooks.
CS-Cart version and edition compatibility
CS-Cart version
CS-Cart
CS-Cart Ultimate
Multi-Vendor
Multi-Vendor Ultimate
4.22 and later
Testing next
Testing next
Testing next
Testing next
4.21.2
Supported
Supported
Tested
Supported
4.20.x
Supported
Supported
Supported
Supported
4.19.x
Supported
Supported
Supported
Supported
4.18.x
Supported
Supported
Supported
Supported
4.17.2
Tested
Supported
Tested
Supported
Before 4.17.2
Not supported
Not supported
Not supported
Not supported
Last tested build: Multi-Vendor 4.21.2, Oct 17, 2026Tested on: Multi-Vendor 4.17.2, CS-Cart 4.17.2, Multi-Vendor 4.21.2
Orders: the recommendations come from your orders. A store without enough orders shows popular products of the same category until enough pairs exist (setting)
Requirement
Recommended: a cron job that rebuilds the data once a day. Without cron the add-on rebuilds after an admin page view when the data is older than the rebuild interval
Core changes
None. Hooks and template overrides only
1.0.0
Oct 17, 2026
Latest
Added 9
Recommendations computed from completed orders in batches: order statuses, history window, recency half-life, minimum support and confidence, order size limit, excluded categories; cron command, cron URL, admin fallback and Rebuild now.
Product page block (Amazon style): checkboxes, combined price per selection, Add all to cart in one AJAX request, the viewed product added with the options picked in the product form.
Cart page block "Frequently bought with items in your cart".
Bought together tab in the product editor (admin and vendor panel): pinned and excluded products, hide the block.
Category fallback for products without enough order data.
Promotion bonus "Frequently bought together discount" for cart promotions, savings line in the block.
Analytics under Marketing: impressions (visibility beacon), clicks, products added, attributed orders and revenue, daily chart, top products, strongest pairs.
Multi-Vendor: marketplace-wide pairs with same-vendor recommendations; CS-Cart Ultimate: pairs, statistics and display settings per storefront.
Full page cache support (4.21), domain-bound license check, self-healing upgrades.
Tested on Multi-Vendor 4.17.2, CS-Cart 4.17.2, Multi-Vendor 4.21.2. First release.
How is this different from Customers also bought, Buy together and Product bundles?
Customers also bought (CS-Cart) counts every placed order, also failed and cancelled ones, and shows a plain product list without combined price, add-all button or statistics. Buy together and Product bundles need bundles you build by hand. This add-on learns the sets from completed orders (with recency, support and confidence), shows them with one Add all to cart button, lets you pin and exclude products, gives an optional bundle discount and measures what the blocks sell. You can keep the core add-ons for a few hand-made bundles.
My store is new. Will the block be empty?
With the default setting the block shows popular products of the same category until enough orders exist. Lower Minimum orders per pair to 1 for small stores, or pin products by hand.
How often are the recommendations updated?
Once a day with the cron job (or after an admin page view when the data is older than Rebuild every, hours). Rebuild now on the analytics page updates them at once. Pins and exclusions apply immediately.
Does it slow down my store?
No. The heavy work runs in batches by cron or after an admin page has been sent. A product page reads a few rows from an indexed table, and the result is cached by CS-Cart.
Does it work with the full page cache of CS-Cart 4.21?
Yes. The block is the same for every visitor, and impressions are sent by a small beacon after the page is shown.
Why is a product not recommended?
It is out of stock, has no price, needs a minimum quantity above 1, has a required text or file option, is hidden on this storefront, belongs to an excluded category, is excluded for this product, or (Multi-Vendor) belongs to another vendor.
Can I give a discount for buying together?
Yes, with a cart promotion and the bonus Frequently bought together discount (see Usage). Only products added through the block for the same product are discounted, and only when that product is in the cart too.
What happens if the license lapses?
Without a valid license (no key after the 14-day start period, an invalid or revoked key, a domain the license does not cover, or no successful check for 14 days), the Frequently bought together blocks are hidden and recommendations are no longer rebuilt. Carts that already contain a bought-together set keep their discount; your data and statistics are kept. Once the license is valid again, everything is back.
The admin panel shows a license notice.
Open Add-ons → Manage add-ons → Frequently Bought Together & Cross-sell: the License card at the top says what is wrong: no key, a key for another add-on, a revoked license, or a domain that the license does not cover. Fix it on the License tab and click Check now. See License.
Does the add-on work on my staging copy?
Yes. Subdomains of your licensed domain (for example staging.example.com) and local development hosts (localhost, private IP addresses, .local, .test) are covered by the same license.
What happens if your license server is down?
Nothing changes for 14 days: the add-on keeps working and retries every hour. Only if no check succeeds for 14 days is it switched off until the next successful check.
Does the license check slow down my storefront or checkout?
No. The check runs only in the admin panel or from cron, at most once a day, never while customers browse or check out.
