STAR stands for Situation, Task, Action, Result. Every behavioral answer follows this format.
Situation: sentences of context. "I was on a -person team building a recommendation engine."
Task: Your responsibility. "I owned the ranking algorithm."
Action: What YOU did. Use "I" not "we." Describe specific decisions you made.
Result: Quantified outcome. "Engagement increased % and latency dropped from ms to ms."
Keep each answer under minutes.