Sev1 at 2am
You are on call at a scale-up when checkout starts failing at 2am, hours before the biggest sale of the year. Triage, mitigate, communicate, and own the aftermath.
the situation
You are the on-call engineer at a 120-person e-commerce scale-up. At 02:14 your phone goes off: checkout error rate is at 40 percent and climbing. The last deploy to the checkout service went out six hours ago and looked healthy. Revenue stops when checkout stops, and the company's biggest sale of the year starts at 9am with triple the normal traffic. You are the only engineer awake. The dashboards exist but nobody has looked at some of them in months.
what this interview covers
- Orientation under pressure
- Design calls with missing information
- The incident, live
- Trade-off interrogation
- Retrospective and ownership
How the interview works
One scenario, 45 minutes, hard stop. The interviewer works through the situation with you - design, incident, trade-offs - and will not confirm or correct anything until the debrief. There are more questions in the arc than most people reach; how far you get matters less than how well you reason. Saying you do not know and moving on beats bluffing. When time runs out, you are graded on everything you covered.
about this interview
About
It is 02:14 and your phone is going off: checkout is failing at a 120-person e-commerce company, revenue is bleeding, and the biggest sale of the year starts at 9am. You are the only engineer awake. This interview walks that night start to finish - the first five minutes, the mitigation calls, the moment your prime suspect turns out to be innocent, the 5am go/no-go on the sale, and the postmortem you write afterward.
The interviewer plays a senior engineer running a real screen. They will push on your answers and ask why, and that is normal, not a signal that you are wrong. What they will not do is confirm, correct, or hint at how you are doing while the interview is running. If you do not know something, say so and move on - bluffing costs more than honesty here.
You get 45 minutes and the stop is hard: when time runs out, the interview ends wherever you are, exactly like a real screen. After that you get the debrief real interviews never give you - what each answer showed, what a strong answer looks like, and an overall hire signal based on everything you covered.