Articles on: How Ecto Works

How Ecto decides which cart to keep

Ecto is designed to keep cart synchronization simple, invisible, and predictable.
To do that, it follows a clear rule:
👉 Ecto always keeps the most recently edited cart for a logged-in customer.
At any time, only one cart per customer is stored.

When a cart is saved

Ecto saves carts only for logged-in customers.
Once a customer is logged in, Ecto listens to cart actions such as:

adding a product
updating quantities
removing items

Each of these actions updates the cart’s last modification time, which Ecto uses to determine which cart is the most recent.

If a customer creates or edits a cart before logging in:

the cart exists only on the customer’s device
no cart data is sent to Ecto yet
Ecto cannot associate the cart with a customer

This cart is not immediately considered the active cart.

When the customer logs in, Ecto compares the two cart versions:

the cart currently on the customer’s device
the cart already saved in Ecto

If the cart saved in Ecto is more recent, it is restored on the customer’s device.
Otherwise, the cart on the customer’s device becomes the new saved reference.
This comparison ensures that the most relevant cart is always kept.

Cross-device example

A customer builds a cart on desktop at 10:00 while logged in

→ Cart A is saved in Ecto

On mobile, the customer adds items at 10:10 before logging in

→ Ecto is not aware of this cart yet

The customer logs in on mobile at 10:15

→ Ecto compares both carts
→ The mobile cart is more recent and replaces Cart A

If Cart A had been more recent

→ It would have been restored on the mobile device instead
This behavior is expected and intentional.

Why Ecto works this way

This logic avoids:

outdated carts overwriting newer ones
conflicts between devices
popups asking customers to choose a cart

Ecto always prioritizes the most recent cart activity.

Key takeaway

Ecto saves carts only for logged-in customers
Ecto keeps one cart per customer
Cart synchronization is based on last modification time
The most recently edited cart always wins

Updated on: 24/08/2026

Was this article helpful?

Thank you!