Cart Sync keeps a logged-in shopper's cart consistent between your online store and your Tapcart app. Add an item on web, and it appears in the app. Add in the app, and it appears on web. When a shopper builds a cart on your site and leaves, you can also recover that cart with an app push after a window you choose.

What shoppers experience

Two-way sync. Cart changes on web and in the app stay aligned for the same logged-in customer.
Abandoned-cart push. If a shopper abandons a cart on web, Tapcart can send an app push (for example, "You left something in your cart") that opens the app with the cart ready to check out.
Native Shopify checkout. Checkout stays 100% native Shopify on both surfaces. Tapcart does not intercept checkout.
Logged-in only. Guests are untouched. Sync activates only after a shopper logs in.

How it works

When a logged-in shopper's cart changes on either surface, Tapcart syncs those line items to a cart record keyed to their Shopify customer account. Each surface reconciles against that record.

Merging is item-level: the newest change wins per item, and deletions stick.
A purchased cart cannot reappear from a stale device.
Sold-out or zero-quantity lines are ignored.
Cart data is stored per customer and auto-expires after 10 days of inactivity.

Requirements

Your app must be on Tapcart React Native release 21.8.0 or newer.
Shoppers need customer accounts (classic or New Customer Accounts).
Tapcart must enable Cart Sync for your app. Contact your AM or reach out through LiveChat if you do not see Settings → Cart Sync in your dashboard.

Setup paths

Shopify theme storefront: Enable Cart Sync in the Tapcart dashboard, then turn on the Tapcart Cart Sync app embed in the Shopify theme editor. See Enabling Cart Sync on Your Shopify Theme.
Headless / custom storefront: Allowlist your storefront origins, then add the Cart Sync SDK to your frontend. See Cart Sync for Headless Storefronts.

Abandoned-cart push

In Settings → Cart Sync you can:

Set the Abandoned Cart Window (hours a cart can sit idle before the push fires; default is 4).
Turn Abandoned Cart Push Notifications off if you already run your own abandonment flow (for example, Klaviyo email). Cart Sync continues to work either way.

For the push to send, Abandoned Cart Push Notifications must be on, the cart must idle for the full window with the latest activity on web, and the shopper needs an active push-enabled device. A successful send is not repeated for the same abandonment.

FAQ

Does Cart Sync touch checkout?

No. Checkout remains native Shopify on both web and app.

What about guest shoppers?

Guests are unaffected. Sync starts only after login on a surface.

Can I exclude certain items?

Yes. You can exclude specific variants, products, or line-item property patterns (for example, gift-with-purchase or bundle lines) from the Cart Sync settings in your dashboard.

What data is stored?

Cart line items keyed to the Shopify customer ID. Records auto-expire after 10 days of inactivity and are cleared when an order completes.

Cart Sync: Keep Carts in Sync Between Web and App