As a user of grocery ecommerce an issue that I often have is with replacements. Most orders have at least one replacement but I’m never given a choice of what to substitute with. The ideal solution would of course be to always have stock, but since that’s nearly impossible the second best solution would be to give me a choice of replacement.

Here’s a mockup of what that might look like on Tesco’s site:

Of course, I’ve little insight into their operations but purely from the platform perspective it seems simple enough to implement.

They definitely have historical data of products that are often replaced. They probably have at least some sort of stock level indication.

Those two data points can be used to display the alternative selection only for some products and to suggest alternatives that are rarely replaced.

While impact of this should be tested on checkout rates, I’d think this would increase confidence and long term satisfaction.

If the user doesn’t select one then the system is no worse compared to current situation.