If I was building software to automatically underbid products being sold in an online store, I would for sure want some safeguards in place to prevent this. I would almost expect this kind of scenario playing out as an eventuality. I realize this was a bug and that the code otherwise works, but they've obviously got a single point of failure. There should be some redundancy in the design, but I guess that's fairly obvious now.

A few things they could do (as told from my mighty armchair of wisdom):

* slow roll out of new code so not everyone is impacted (assuming service architecture permits)

* alert/circuit-breaker on changes to qty sold versus order totals; compare with historical data

* request approval on price changes before they apply

* prevent or notify on price changes exceeding X% amount relative to last week or month

* circuit-breaker on significant uptick in order count compared to average

* and of course, better QA and validation of their code and systems

I think it's safe to say RepricerExpress will be putting some safeguards in place to prevent this from happening again. Or they'll just go under from the customer flight. Or it's a scrappy PHP script that they'll update in notepad and call it a day.

I'm not terribly familiar with UK law, but it seems like RepricerExpress would be at least partly responsible for the lost money, assuming that minimum prices were set and not respected by the software. But if it's just a case where competing users of the software were automatically undercutting each other with no defined minimum, then maybe not.

Not a good situation to be in.