These are the projects I would walk an interviewer through. Each one starts with who was waiting, then what we changed and what I would do differently next time.
Planners booked doors in a spreadsheet that synced every hour. We built a scheduler with live conflicts, carrier self-service and an override button for the yard manager. Missed slots fell by thirty-eight percent in the first peak season. Next time I would ship the override button in week one; planners trusted the system faster once they knew they could beat it.
Port positions arrived from four vendors in four formats. A Flink job now normalises them into one arrival event per container, with a confidence score the warehouse screen can show. The hard part was not the stream; it was agreeing with planners on what late actually means.
Haulage firms were paid from a mutable table and disputes took weeks. The append-only ledger with nightly reconciliation made every payout traceable to a delivery note. I would add the dispute screen earlier; finance spent months asking engineers to run queries for them.
Send me a short description and I will tell you honestly whether I have solved something close to it.