The €9,400 weekend

The problem, hour by hour

Friday 17:20, a checkout template ships; the purchase event stops firing. Nothing looks wrong anywhere: the site sells normally, revenue lands in the shop system, and Google Ads simply sees a store that stopped converting. Friday night, Smart Bidding begins responding to the famine the only way it can, chasing whatever still registers, and by Sunday it is buying cheap, junk-adjacent traffic at volume. Monday is a public holiday. Tuesday 09:30, a finance colleague asks why ad spend is up while reported revenue from ads is zero, which is how the marketing department learned about it: from accounting.

The direct damage came to €9,400: a weekend of spend optimized toward noise, plus the following week's bidding running on poisoned learning. The indirect damage was worse and does not fit a number: three weeks of target re-basing, a postponed campaign launch, and a standing meeting titled "how do we make sure this never happens again" that produced, at first, nothing but a shared spreadsheet someone was supposed to check.

The approach, eventually

The fix that stuck was embarrassingly small: a script that compared conversion volume against a rolling baseline every half hour and shouted when the line went quiet. Version one was 80 lines and ugly. It caught its first real incident within a month, a consent-banner update that silently blocked tags, the same failure class Google's Consent Mode v2 rules have made common across the EEA since 2024. The script grew the other four checks, the checks grew alert templates, and in 2025 the spreadsheet-era ended for good when Lena and I turned the stack into this company.

The result, measured properly

The 2024 recurrence is the controlled experiment. Same retailer, same class of failure, another Friday-evening release. The heartbeat check tripped at minute 38; the on-call pause landed at minute 49; total damage €130, and the Monday retro took eleven minutes. Nothing about the team got smarter between the two incidents. The difference was purely that silence had been made audible, which is the entire thesis this company runs on, and why every account we touch gets the monitoring layer before it gets an opinion.

One wider number for scale: invalid traffic alone wasted an estimated $63 billion of global ad spend in 2025. The industry is very good at talking strategy over the sound of small leaks. We built a company around hearing them, and the follow-up mechanics live in the tracking-failures guide.