Error rate spike after deploy
You're on call for a single web API. Ten minutes ago the error-rate dashboard jumped from ~0.1% to ~40% of requests returning HTTP 500, and latency on the success path is unchanged. The deploy timeline shows a new version went out 12 minutes ago; nothing else changed (no traffic spike, no dependency alerts). The on-call channel is filling up with customer reports. How do you triage and mitigate?
What a strong answer looks like
Stop the bleeding first (mitigate), then form hypotheses from real signals. Separate root cause from symptom, communicate status as you go, and close with what prevents a repeat.
0:00 of about 15 min
Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.
Run or narrate your approach, then ask the coach.