Case Study · Retail
Defacto Sorting: which product sits where on the category page — the brain behind smart sorting
A dynamic scoring algorithm that decides the order in which products appear when a category page opens on defacto.com. It weighs sales, clicks, broken size runs, stock and shelf life together, with a cold-start solution for new products and scenario-based weighting.
- 5
- Signals
- Cold start
- New products
- Weight sets
- Scenarios
- Live
- Status
Sales, CTR, broken sizes, stock, shelf life
Placed from look-alikes until data accumulates
Campaign, season end, new collection
Since 2021
Problem
Every e-commerce site has an option called “smart sorting”: when a customer enters a category, products appear in some order. That order directly determines which product gets seen and sold. With thousands of products and stock and sales velocity changing daily, managing that order by hand is not feasible; leaving it to a fixed rule either keeps the best seller on top forever or never gives a new product a chance.
Solution
Sorting is a dynamic algorithm that computes a score for each product and orders the category page by it. The signals in the score:
- Sales count — recent performance
- Click-through rate (CTR) — interest relative to impressions
- Broken size runs — a product missing sizes disappoints the customer; it moves down
- Stock status — is there enough stock to display
- Shelf life — the product’s age within the season
These signals are combined with weights, and the weights change per scenario. Different weight sets are defined for different goals, such as clearing stock during a campaign or pushing the new collection at the start of a season.
Two additions complete the picture. Cold start: a new product has no sales or click data; the algorithm starts it from the position of similar products and moves to its own score as data accumulates. User interaction: when the customer picks a filter or a sort option, the algorithm runs with those parameters; the smart order stays valid inside the user’s choice.
System
The score is computed in the DSO’s database and in Python, and the result is integrated into the e-commerce platform. Lumtify coded the project, integrated it, and maintained and developed it until the end of 2024.
Outcome
Sorting went live in 2021 and has set the order of defacto.com’s category pages ever since. While bringing the most relevant product forward for the customer, it also supports stock management: broken products move back, products with stock to display move forward.