Start with the highest-severity issue you've personally owned, the one that pushed your limits.
This is a fill-in question and the page treats it that way: the blanks are yours, and a borrowed story does not survive the follow-up, which is almost always about a number. What can be taught is the ordering, because the ordering is what makes an incident story land in ninety seconds instead of five minutes. Most people tell it as a narrative, in the sequence events happened, and the useful information ends up last. Panels want stakes early, diagnosis in the middle, and a guardrail at the end. There is also one structural choice that raises credibility more than anything else you can say, and most candidates leave it out. This page covers the shape and that choice.
What the interviewer is scoring
They score: did YOU own it (not 'the team'), what was the blast radius, what did you rule out, and what guardrail did you leave so it can't recur.
In short: This is a signal probe, not a trivia question, they want scale, ownership, and a decision made under pressure. Structure beats storytelling.
The scaffold for your own answer
- The full 90-second answer, written first person, the way you would actually say it
- How I reason through it: the mechanism, the decision points, and where the claim stops
- A fill-in scaffold for your own story: the beats, the timing, and the follow-ups it invites. We do not write the incident for you.
- Worked responses to the 3 follow-up probes listed above, plus the traps that lose the point
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How to reason through it
- Open with scale and stakes in one line: system size, throughput, who was affected.
- State the signal you actually saw, before naming the cause.
- Name the two or three hypotheses you ruled out and the check that ruled each one out.
- State the fix and specifically why it was safe to apply under live load.
- Close with the guardrail: the alert, runbook, or configuration change you left behind.
- Anchor every number to something you could defend if the panel pushes.
What I would verify
- Have the numbers ready and sourced: duration, affected volume, how you knew it was over.
- Be precise about your own scope if several people were on the call.
- Keep at least one wrong turn in the story; real incidents contain them.
- Know what the guardrail would have caught and what it still would not.
Follow-ups they push on
- What would you do differently?
- How did you know it was actually over?
- What was your part specifically?
The probes are open. Pro carries the spoken scaffold, the beats, and the follow-up handling, including a worked response to each of these.
Concepts tested
Learn it, run it, then say it
Three steps, in order. Nothing here is a detour.
1 · Learn the mechanism
Understand it before you try to say it.
2 · Practise it for real
Run it once so the answer describes something you have seen.
3 · Rehearse the next question
Keep going while the mechanism is fresh.
Questions that go with this one
- senior · ProA customer says “the database is down.” In five minutes, how do you separate a broken connection path, connection saturation, wrong-node routing, lock waits, and a query-specific failure—and what do you communicate before you know root cause?The live version of the same skill, where the story you will tell later is actually created.
- senior · ProWhen we find a bug we send the patch upstream to pgsql-hackers. Have you worked that way, finding something nobody had flagged and driving it to a fix?The other question where your own history is the answer and the structure is the coaching.
- senior · ProA fintech tenant must never read or write another tenant’s rows. Show the effective-role threat model across GRANT, RLS, table ownership, referential integrity, and SECURITY DEFINER functions.If your worst incident involved data reaching the wrong tenant, that story lands here.