Engineering decisions behind a trustworthy price app

You cannot bolt trust onto a shopping app at the end. It is the product of dozens of engineering choices: how fresh the prices are, how offers are sourced, how variants are matched, and what the ranking is allowed to optimise for.

Freshness is credibility

A price from last week is a rumour. The data pipeline is built so that what a shopper sees reflects what a retailer is charging now, and where it does not, we are honest about the timestamp.

Never rank on commission

The fastest way to destroy a price app is to let money decide the order. The ranking optimises for the lowest trustworthy price for the shopper. That single rule is what makes every other feature believable.