Persistent Cart — Setup & Testing Guide

01 — Before you start

Requirements

A Shopify store on any plan (the Free app plan is enough to run and test the core feature).
Customer accounts enabled. Cross-device sync only works for logged-in customers. Set this under Settings → Customer accounts.
An Online Store theme where the App embed can be enabled (any Online Store 2.0 theme).

Platform limit

Guest (not-logged-in) carts are stored locally on the device and cannot sync across devices. This is a Shopify constraint, not an app limitation — cross-device restore requires a registered, logged-in customer.

02 — Two minutes

Installation

Persistent Cart activates from your Shopify Admin. No code, no developer. Two steps: install the app, then enable its Theme App Embed.

Install the app from the Shopify App Store listing and approve the requested access. You land in the embedded admin dashboard. The default plan is Free.
Enable the Theme App Embed (required). Go to Online Store → Themes → Customize → App embeds, toggle on “Persistent Cart”, then Save.
Done. Carts now persist for logged-in customers, and the “Share this Cart” button appears on the cart. Setup takes under 60 seconds.

This step is mandatory

Without the App embed enabled, no functionality runs — no persistence, no share button. If something isn't working, check the embed toggle first.

Get started

You choose a plan on Shopify's plan page when you first open the app. The Free plan needs no payment.

Go to Online Store, then Edit theme, then App embeds.
Turn on "Persistent cart" in the App embeds list.
Click Save.

Once saved: logged-in customers keep their cart across devices, and a "Share this Cart" button appears on the cart.

Shipping calculator (optional)

The cart can show a shipping estimate before checkout. It is a separate block, so it appears only where you place it.

Go to Online Store, then Edit theme, then open the Cart template.
If the Cart template has no Apps section, click Add section and choose Apps.
In the Apps section, click Add block and choose "Shipping calculator".
Click Save.

The estimate uses your store's own shipping rates, for the cart the customer is looking at. It needs a Shopify-hosted theme: on a custom storefront the block does not appear.

Not working? Check these in order:

Is the App embed turned on? Without it, nothing runs: no cart persistence, no share button.
Is the customer logged in? The app saves and syncs carts for logged-in customers only. A guest's cart is Shopify's own browser cart, so it stays on that device.

03 — Optional

Configuration

Defaults work out of the box. To customize, open the app's Settings page in the embedded admin. Settings are saved to your shop and read by the storefront automatically.

Setting	What it does	Plan
Cart conflict modal	When a shared cart meets an existing cart, show a Merge / Replace / Cancel dialog instead of auto-merging.	All plans
Share cart icon	Show the share button and pick its style (link / share / cart icon).	Pro+
Redirect to checkout	Send the customer straight to checkout after a cart is restored.	Paid
Cart expiry	How long an inactive saved cart is kept (7 / 14 / 30 / 60 days). Free is fixed at 2 days.	Paid
Custom CSS classes	Hook the share button and conflict modal into your theme styles.	Pro+

04 — Verify it works

Testing

Cross-device persistence

Log in as a customer on the storefront and add a few products to the cart.
Open the store on a second device or browser, logged in as the same customer, with an empty cart.
Load any page. The saved cart is restored automatically and the page reloads with the items back.

Share this Cart

On the cart page or cart drawer, click “Share this Cart” (next to Checkout). A short link is copied to the clipboard.
Open that link in another browser. A “Merging your cart…” overlay appears and the items are added.
If you already had items and the conflict modal is on, the Merge / Replace / Cancel dialog appears.

05 — Compliance

Data & privacy

What the app stores. For a logged-in customer, the app stores their numeric Shopify customer ID, the products and quantities in their saved cart, and a one-way hash of the cart token, never the token itself. With the customer's marketing consent, it also records clicks on shared cart links by channel, and the orders that came from them or from a restored cart. It does not store customer names, email or postal addresses, phone numbers, payment information or device fingerprints. About the store, it keeps the shop domain and the store contact email for service notices.
GDPR webhooks implemented: customers/data_request, customers/redact, shop/redact.
Retention: saved carts and share links expire after 2 days on Free and 7 days on Basic; on Pro and Advanced you choose 7, 14, 30 or 60 days (default 30 and 60). A daily cleanup deletes expired records. Order attribution records are kept for at most 365 days. On uninstall, the store's customer data is deleted within 30 days.
Full policies: Privacy · Terms · Cookies · DPA.