F12 Labs
CartSync ProCartSync Pro documentation / Help
Plans, limits and troubleshooting
What CartSync Pro costs, every limit it has (signed-in customers only, what a saved cart holds, how often it saves, Cart Helper search and gift messages, the 30-day attribution window), and fixes for common problems across the app, with links to each page's own troubleshooting.
This page lists what CartSync Pro costs and every limit it has, then the problems merchants run into most. Each page in these docs also has its own troubleshooting section; the links below take you there.
Plans
CartSync Pro is free. There's no paid plan and nothing is locked: cart sync, Cart Helper, free gifts, draft orders, cart history and Insights all work on every store. There's no limit on the number of customers or saved carts.
Limits
| What | Limit | Details |
|---|---|---|
| Who gets cart sync | Signed-in customers only | Guests keep their cart in their browser, as on any Shopify store. See Who it works for |
| What a saved cart holds | Products (variants) and quantities | Line item properties, the cart note, cart attributes, discount codes and subscription choices aren't saved. See What's saved |
| Storefronts | Online Store themes | Cart sync is a theme app embed. Headless storefronts (Hydrogen or a custom front end) and other sales channels don't run it |
| Themes | The theme the embed is on | Turn the embed on again after switching to another theme |
| Saves per customer | 30 a minute | A save over the limit is skipped; the next change to the cart saves the whole cart again |
| Another device catching up | On a page load, on switching back to the tab, or after the Idle Timeout (15 to 120 seconds, 30 by default) | Not a live feed. See When another device catches up |
| Items put back | In stock, published to the Online Store | Out-of-stock, draft, archived and deleted variants are left out, and the restore notice says how many |
| Customer search in Cart Helper | At least 3 characters; up to 20 results | Matches first name, last name and email |
| Stock in Cart Helper | Locations your Online Store sells from | Other locations don't count |
| Gift message | 60 characters | See Free gifts |
| Cart history | 50 versions at a time, then Load older versions | A customer's changes within 10 minutes of each other are one version. See Cart history and restore |
| Credit for an order in Insights | Products restored to that customer in the 30 days before it | See How an order is credited |
| Customer's Active Cart block | Shopify admin on desktop | Shopify doesn't show app blocks on mobile. See The customer's cart on their Shopify admin page |
| Staff roles | None | Every staff member who can open CartSync Pro can use every part of it |
The cart doesn't follow the customer
Check, in order:
- The app embed is on. The CartSync Pro home page says Cart sync across devices with an On badge, and names your live theme. If it says Cart sync across devices is off, click Turn on in theme editor, then Save. See Getting started.
- You recently switched themes. The home page checks your live theme. If it now says off, turn the embed on in the new theme.
- The customer is signed in on both devices, to the same account. A guest cart isn't saved.
- The second device has caught up. Open a new page, or switch away from the tab and back.
- The cart is saved. Open Cart Helper, select the customer and look at Current Cart. If it's right there but not on the storefront, turn on Enable Debug Logging in the embed settings (see Debugging) and look at the browser console on the storefront. Turn it off again when you're done.
Items come back after the customer removed them or ordered
The customer still had them in the cart in another browser, and opening a page there saved them again. Opening a page keeps items that are only in that browser's cart; switching back to an already-open tab matches the saved cart exactly. See After an order.
To fix one customer's cart, remove the items in Cart Helper's Current Cart and click Save Changes, or click Clear Cart. Clear Cart also empties the cart in the customer's other browsers the next time they open your store.
Quantities doubled
The same product was in the guest cart and in the saved cart when the customer signed in, so the quantities were added together. See Signing in with a guest cart. In Cart Helper, it happens when you choose Merge Quantities (Add Together) for a product already in the cart.
An item didn't come back
It's out of stock, or the variant was deleted, archived or unpublished from the Online Store. The restore notice says how many items couldn't be added. A personalised item comes back without its personalisation: line item properties aren't saved.
Cart Helper shows no saved cart, but the customer has one
If the Customer's Active Cart block on the customer's page shows items but Cart Helper says No items in cart, check how many metafields the customer has in the custom namespace (customer page → Metafields). Cart Helper reads the customer's first 10 of them, so on a store with many customer metafields it can miss custom_cart. Email support@ftwelvelabs.com before saving a cart for that customer in Cart Helper: a save there can replace the cart they have.
Problems on other pages
| Problem | Where to look |
|---|---|
| The restore notice doesn't show, is hidden, or is hard to read | App embed settings |
| Products added in Cart Helper don't reach the customer, or stay Pending | Cart Helper |
| A free gift was charged, or Create draft order is greyed out | Free gifts and draft orders |
| No cart history, or a version looks wrong | Cart history and restore |
| The block isn't on the customer page, or a line says Unknown product | The customer's cart on their Shopify admin page |
| Insights are empty or an order isn't counted | Insights and attribution |
Still stuck
Email support@ftwelvelabs.com with your store's myshopify.com address, the customer (name or email), what they did on which device, and what you expected to see. If you turned on debug logging, copy the browser console output from the page where it went wrong (cart lines start with [Cart Tracker]).