Start with the problem
Give the interviewer enough context to understand the work. Who needed a change, what was failing, and what made the problem worth solving? Describe the constraints before naming your tools. If you do not have exact measurements, explain what you observed rather than inventing a number.
Separate your work from the team's outcome
Use 'we' to explain the shared goal, then 'I' to define your contribution. Name a decision you made, a failure you investigated, or a change you delivered. Be equally clear about the work owned by other people. A precise boundary is more useful than claiming every part of a project.
Explain one real trade-off
Choosing a tool is not the whole decision. Explain the alternative, the constraint that mattered most, and the cost you accepted. A cache may reduce read latency while making invalidation harder. A staged launch may reduce risk while delaying access. Prepare to explain both sides.
Bring the result back to the original problem
Explain what changed and how you checked it. The outcome might be a comparable measurement, less manual work, fewer failures, or a discovery that the approach had limits. Record a two-minute answer and check whether the listener can identify your action and its effect.