Designing for habitual shopping in e-commerce
Case study by:
Osiris Ramos
Date:
September 2026
Filling a gap
Shopping lists have become a ubiquitous feature in e-commerce, allowing customers to plan shopping trips, save items for later, and catalog their frequently purchased items. Sentier’s client, a brick and mortar retailer, lacked a shopping list feature on their e-commerce website and mobile app. Through customer feedback and competitive analysis, it became clear that adding this feature would boost customer retention and loyalty. We stepped in to fill that competitive gap.
The goal
Our client wanted to support the full range of ways customers plan and shop, whether they're building a digital order or walking the aisles in person. That meant designing shopping lists for real, varied behaviors, including saving items for later, grouping products according to specific occasions, listing items in the order customers might walk through the store, and even sharing a list with a partner or roommate.
The business case was just as clear. A strong list feature promotes deeper digital engagement, better insight into customers’ shopping habits, and more opportunities to merchandise and recommend products. The addition of shopping lists also needed to lay the groundwork for features already on the roadmap that would personalize the customer experience even further.
These objectives shaped every design decision from there: the feature had to serve planners and browsers alike, work equally well online and in-store, and scale cleanly into whatever came next.ating SNAP-eligible items
The challenge
Although the initial request, “Add a shopping list feature,” was straightforward, the real challenge was more nuanced. Because customers use shopping lists for a wide variety of purposes, the team needed a solution that would satisfy all types of shoppers.
The feature also needed to remain lightweight enough to fit naturally into the existing cart and product browsing experience. After conversations with stakeholders revealed these key criteria, I set out to determine how granular the list functionality should be.
The approach
I conducted competitive research to uncover patterns in shopping list UIs, and then used a feature matrix to compare and contrast retail competitors’ shopping list features in discussions with product.
I identified two primary interaction models:
Allow customers to assign quantities within the list itself, so those quantities automatically transfer to the cart. This option is better for weekly planning and repeat purchasing, but it could be more cognitively demanding and potentially confusing because more interaction is required.
Let customers quickly save items for later without predefined quantities. This option requires fewer taps, potentially making it more intuitive. The tradeoff would be a slower order-building process (not great for planners).
I partnered with Elle, our embedded design researcher, to conduct unmoderated comparative user testing. Based on the findings from that research, I designed a flexible system allowing customers to create multiple lists, add items directly from product cards or product pages, check off items while shopping in store, and transfer individual items or an entire list into the cart.
Next, I worked closely with Cliff, our embedded mobile designer, to create scalable UI components designed to support future enhancements. This will help the client modernize other pages and features across the website and mobile app in a more consistent and easy to manage system.
Results & impact
The shopping list feature closed a competitive gap and directly responded to frequent customer requests. Even without any marketing for the new feature, a large portion of online shoppers began using the feature within the first week of its launch. After only four days, nearly 1,000 customers had created and added thousands of items to their first shopping lists.
Customers gained a dedicated space to save and organize items, reducing the need to rebuild carts from scratch. The product owner gained credibility among their team with another successful feature launch. Shopping lists also laid the foundation for future initiatives such as revamps to the order details, cart, and checkout pages across the website and mobile app.
If your team is weighing flexibility against simplicity in a feature decision, we'd be glad to compare notes.