Name the problem
Given a symptom, say what it really is in professional terms — the precise concept, the one-line senior framing, and the fix category. This is how you sound senior when you diagnose out loud.
0/10 done
- Requests hung waiting for DB connections during a slow callUnder load, requests piled up waiting for a database connection — while each was making a slow external API call inside its transaction.
- Why is manufacturing experience relevant to Opendoor?The interviewer asks: your background is manufacturing, inventory, and financial systems — why does that transfer to homes, offers, and pricing?
- A retried request charged the customer twiceThe client's network blipped, it retried the same charge, and the customer was billed twice.
- Two instances generated the same IDTwo service instances both read the current sequence value and each handed out ID 101. Now you have a duplicate primary key.
- An offer jumped from CLOSED back to ACCEPTEDA status update moved a CLOSED offer back to ACCEPTED — a move that should be impossible.
- A scheduled job ran on two servers at onceThe nightly batch fired on every app instance, so it ran several times and double-processed.
- A task disappeared when processing threwA worker hit a transient error, logged it, and moved on — and the task was simply gone.
- Two users edited the same record; one change vanishedTwo people opened the same offer, both saved, and the first person's edit silently disappeared.
- Events applied in the wrong order gave a wrong final stateA stream of status events arrived out of order, you applied them as they came, and a home ended in the wrong final state — and a duplicate event got applied twice.
- Users saw an old value after an updateSomeone updated the price, but the listing kept showing the old price for a while.