Sync customers, marketing consent, orders and abandoned checkouts to Klaviyo or Brevo, with a consent log.
Tested on 2 buildsUpdated Nov 3, 2026Version 1.0.0CS-Cart, Multi-Vendor 4.17.2 – 4.21.x No core file edits
Built for
Email Marketing Connect: customers, marketing consent, order events and abandoned checkouts synced to Klaviyo or Brevo, with a consent log1 of 7
What it does
For stores that run their email marketing in Klaviyo or Brevo and need clean, consented data from CS-Cart. You use your own account and API key; their plans and limits apply. The add-on sends profiles, list subscriptions and events from the server, so no tracking script is added to your pages. All flows were tested against a local server that answers like the Klaviyo and Brevo APIs; a test with your live account is up to you.
How it works
Choose Klaviyo or Brevo, paste the API key, pick the subscriber list and test the connection. Shoppers see an unticked opt-in checkbox at checkout and on the registration and profile forms. Every change becomes a job in a queue that is sent right after the page or by cron, with retries on errors. Marketing, Email marketing sync shows waiting, sent and failed jobs, the consent log with CSV export and the history import.
Features
Klaviyo (private API key) or Brevo (API key v3), your own account
Opt-in checkbox at checkout, registration and profile, with your own text
Consent log with time, source, consent text and IP, CSV export
Subscriptions and unsubscribes synced to the list you choose
Customer profiles with name, phone and address
Placed Order, Ordered Product, Fulfilled and Cancelled Order events, once per order
Started Checkout for abandoned checkout flows
Viewed Product for signed-in customers, server side
Queue with retries, Send now, cron job and a sync dashboard
History import of customers, subscribers and past orders
Bridge for the subscriptions of the core Newsletters add-on
Klaviyo catalog feed URL and daily Brevo product sync
What you get
Package
kv_email_connect-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
Supported
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 4.17.2, Nov 3, 2026Tested on: Multi-Vendor 4.17.2, CS-Cart 4.17.2
Requirements
PHP
CS-Cart or Multi-Vendor 4.17.2 to 4.21.x, PHP 7.4 to 8.3 with the curl extension
Requirement
A Klaviyo account with a private API key, or a Brevo account with an API key (v3). Their plans and limits apply
Requirement
Recommended: a cron job (every 5 to 15 minutes)
Core changes
None. Hooks and template overrides only
1.0.0
Nov 3, 2026
Latest
Added 8
Klaviyo (private API key, revision 2024-10-15) or Brevo (API v3) connection with list selection and connection test.
Opt-in checkbox at checkout, registration and profile; consent log with source, text and IP; CSV export.
List subscriptions and unsubscribes, customer profiles with phone and address.
Events Placed Order, Ordered Product, Fulfilled Order, Cancelled Order, Started Checkout and Viewed Product.
Queue with retries, Send now, cron job and sync dashboard.
History import of customers, subscribers (incl. core Newsletters and Email marketing) and orders.
Klaviyo catalog feed URL and daily Brevo product sync.
Domain-bound license check and self-healing upgrades.
Tested on Multi-Vendor 4.17.2, CS-Cart 4.17.2. First release.
Do I need a paid Klaviyo or Brevo plan?
You need your own account. Free plans work within their limits; the add-on adds no fees of its own.
Is a tracking script added to my storefront?
No. Everything is sent from the server. Viewed Product is therefore only sent for signed-in customers.
Does the checkout wait for Klaviyo or Brevo?
On PHP-FPM hosting the jobs are sent after the page was delivered. On other hosting a few jobs are sent at the end of the request; turn off "Send right after each page" and use the cron job if you prefer.
Which emails are never sent?
Placeholder emails that CS-Cart creates when the checkout does not ask for an email ([email protected]).
What happens to customers who unsubscribe in Klaviyo or Brevo?
They stay unsubscribed there; the add-on never resubscribes anyone without a new opt-in in your store.
Can I keep using the Newsletters add-on?
Yes. With the bridge on, its subscriptions count as consent and are synced; our own checkbox stays hidden where a Newsletters list is shown.
Was it tested with live accounts?
It was tested against a local server that answers like the Klaviyo and Brevo APIs. Please test with your account (Test connection, one test order) before you start flows.