On the Wednesday, a finance reconciliation flagged two hundred and fourteen orders taken over the previous weekend that had been paid for and never dispatched. Four of those customers had already telephoned. Nothing in any log was an error, no alert had fired, and every dashboard for that weekend is green, because as far as our systems were concerned nothing failed. The order service writes the order row, commits, and then publishes an event that fulfilment consumes. On Saturday morning the b...