Amazon LP interview focusing on "Have Backbone; Disagree and Commit."

I told a story about when my manager wanted to use a NoSQL database for a new feature that had complex relational queries. I believed we should use PostgreSQL instead.

I structured it using STAR:

• Situation: New feature for user permissions with role hierarchies and group memberships
• Task: Choose the data store and design the schema
• Action: I built a prototype in both Mongo and Postgres, ran benchmarks on realistic queries, and presented the results to the team. The Postgres version was 5x faster for our access patterns and the schema was cleaner. My manager initially pushed back citing operational complexity, so I also prepared a migration plan and offered to be on-call for the first month.
• Result: We went with Postgres. Six months later, the feature was serving 50k daily users with no issues.

The interviewer then asked what I would have done if my manager still disagreed. I said I would commit to the decision and work to make it successful, while documenting my concerns for future reference.

The key to Amazon behavioral rounds is having 15-20 stories ready, each mapped to 2-3 leadership principles. Don't try to wing it.