Name: Google Merchant API Sync
Brand: Kavio Labs
SKU: KV-GOOGLE_MERCHANT
Price: 99 USD
Availability: InStock

What it does

Google's Content API for Shopping has been replaced by the Merchant API. This add-on connects your store to Merchant Center with your own Google Cloud project, using OAuth or a service account. It suits stores that run Shopping ads or free listings and want changes to reach Google quickly, in several countries and languages, from one admin page. Run it as the channel for a country and language, not next to a file feed for the same one.

How it works

Enter your Merchant Center ID, authorize with Google and register the Cloud project, which Google requires. Add a target for each country and language, map GTIN, brand and Google product category, and run the full sync. The cron job then sends changes, retries failures with back-off, respects Google's quota answers and reads back the status. Multi-Vendor uses one marketplace connection with a vendor filter; Ultimate has targets and mapping per storefront, one domain per Merchant Center account.

Features

Merchant API (v1) product sync with your own Google Cloud project: OAuth 2.0 or service account
Full sync, then incremental sync on price, stock, status and delete; unchanged products are skipped
One data source per country and language, with currency, tax and shipping hints
Attribute mapping for GTIN, MPN, brand, condition, colour, size, gender, age group and Google product category
Queue with retries and back-off, quota aware, no duplicate offers after a timeout
Google status and item level issues with help links, filters and a log with CSV export
Multi-Vendor marketplace account with a vendor filter; Ultimate storefront targets
Register API access and Remove all from Google actions

What you get

Package	kv_google_merchant-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	Supported	Supported	Tested	Supported
Before 4.17.2	Not supported	Not supported	Not supported	Not supported

Last tested build: Multi-Vendor 4.17.2, Nov 7, 2026Tested on: Multi-Vendor 4.17.2

Requirements

Platform	CS-Cart or Multi-Vendor 4.17.2 or later, administrator access
Requirement	A production Merchant Center account with a verified website, and its numeric ID (shown at the top right of Merchant Center). Test accounts cannot be registered for the Merchant API
Requirement	The Google user (or the service account) you connect must have Admin access to that account; registration needs it
Requirement	A Google Cloud project of your own with the Merchant API enabled (API Console, API Library). API keys do not work with the Merchant API; use OAuth 2.0 or a service account
Requirement	A cron job on your server (step 8)
Core changes	None. Hooks and template overrides only

1.0.0

Nov 7, 2026

Latest

Added 8

Initial release: product sync to Google Merchant Center through the Merchant API v1 (productInputs insert and delete), replacing the Content API for Shopping.
Connection with the merchant's own Google Cloud project: OAuth 2.0 (refresh token) or service account (JWT); secrets stored encrypted.
Targets (API data sources) per country and language, with currency, tax percent, shipping hint, category, vendor (Multi-Vendor) and storefront (Ultimate) filters.
Full sync and incremental sync on product save, stock movement, disable and delete; unchanged products are skipped by hash and refreshed after 25 days.
Idempotent sends: a retry after a timeout replaces the same offer; a data source is adopted before it is created; 404 on delete counts as done.
Job queue with back-off (5 min to 12 h), quota aware (HTTP 429), cron by command line and secret address, log with CSV export.
Attribute mapping (GTIN, MPN, brand, condition, colour, size, gender, age group) and Google product category per category, per storefront.
Google status and item level issues read back and shown with filters and help links.

Tested on Multi-Vendor 4.17.2. First release.

How is this different from the Google feed add-ons?

The feed add-ons (Product Feed Pro for Google Merchant Center, Multichannel Product Feeds) publish a file that Google fetches on a schedule. This add-on pushes each change through the Merchant API, deletes removed products at once and reads back the status and the issues. Use them side by side only for different countries or languages: if a feed and this add-on send the same country and language, Merchant Center gets every product twice with the same offer ID. For the same market choose one channel, or set an Offer ID prefix and a different feed label here.

Is the Content API for Shopping still needed?

No. Google ended it on 18 August 2026 and replaced it with the Merchant API, which is what this add-on uses (see Google's sunset notice at developers.google.com/shopping-content/guides/sunset).

Does it work with CS-Cart and Multi-Vendor, and with Ultimate?

Yes: CS-Cart (Ultimate and standard) and Multi-Vendor 4.17.2 to 4.21.x. In Multi-Vendor the connection belongs to the marketplace owner and vendors' products are included through a vendor filter. In Ultimate each storefront can have its own targets and mapping, and shared products are included. One connection is one Merchant Center account, which belongs to one website, so use it for the storefronts of one domain.

Do I need my own Google Cloud project?

Yes. You enable the Merchant API in your own project and use OAuth 2.0 or a service account. Kavio Labs never sees your Google credentials; they are stored encrypted in your own database.

Why do all calls answer 401 UNAUTHENTICATED?

The Google Cloud project is not registered as a developer for the Merchant API. Registration is mandatory and done once per project: open the Connection page, click Register API access, wait about 5 minutes and click Check registration. It needs a production Merchant Center account with a verified website and Admin access for the connected user; test accounts cannot be registered.

Where are my credentials stored?

In your database, encrypted with a key derived from your store's secret. They are never shown again after saving, and the log masks tokens, secrets and keys.

Does it send data to Kavio Labs?

No. The add-on talks to Google only. The license check sends your domain name to the Kavio Labs license server once a day (Kavio Labs downloads).

What if Google is slow or rejects calls?

Failed work is retried after 5 minutes, 15 minutes, 1 hour, 3 hours and 12 hours. When Google answers with a quota error (HTTP 429) the run stops and waits before it continues. A retry after a timeout replaces the same offer, so no duplicates appear.

Why is a product "Not sent"?

It is outside the target's filters, disabled, out of stock with the skip option, or has no usable data (title, main image, price). The Products page shows the reason.

Why does Google still show a product as pending?

Google needs a few minutes to process each change, and the status is read back every 6 hours by default. Use Refresh on the product or Read Google status now.

Are product variations sent as variants?

Yes. Variation products are sent as separate offers that share the item group ID of their parent product, as Google asks for variants.

What happens when I uninstall?

The add-on's data is removed and Google is not called. Click "Remove all from Google" on every target first; otherwise the offers stay in Merchant Center with a frozen price and stock until they expire.