I went through an Amazon SDE-2 loop for an AWS-adjacent team last spring. I had read the leadership principles before, the way everyone reads them, but I had not understood until the loop that they are not a behavioral-round add-on. They are the substrate. Every round, including the coding rounds, was scored on at least two leadership principles in addition to the technical signal.

The Shape of the Loop

The full SDE-2 loop in the loops I sat through was five rounds, all in one virtual onsite day:

Loop layout (one day, ~5.5 hours including a 30-minute break)
  Round 1   Coding (45 min)
  Round 2   System design (60 min)
  Round 3   Coding plus behavioral (60 min)
  Round 4   Bar raiser (60 min)
  Round 5   Hiring manager (45 min)

Each interviewer was assigned two leadership principles to probe. The recruiter sent me a pre-loop email listing which principles to expect overall, but not who was assigned which. So the safe assumption was that any of them could surface in any round.

Round 1: Coding

A medium array problem with a follow-up that turned it into a stream. I solved the base case in about twenty minutes, then walked through how I would adapt the solution if the input arrived one element at a time. The interviewer asked me to estimate the worst-case memory of the streaming version. I did, including a sentence about why the bound was tight.

The behavioral question at the end was about a time I had simplified something. I told a story about removing a service, with the metric attached: the team's on-call pages dropped from roughly three a week to under one a week the month after.

Round 2: System Design

Design a notification system for a retail-style product catalog. The interviewer wanted me to anchor in customer obsession early, which I did by listing three customer-visible signals (delivery latency, duplicate notifications, the cost of a missed notification) before drawing anything. I designed around an event log plus a fan-out worker pool. The interviewer pushed on idempotency for about ten minutes, which is the standard Amazon design-round move in my experience: pick one specific failure mode and grill it.

Round 3: Coding + Behavioral

The coding half was a string problem. The behavioral half had two principles, ownership and dive deep. The dive-deep prompt was: walk me through the most technical thing you have done recently. I picked a query optimization story with the actual EXPLAIN output I had screenshotted from the project, and the interviewer kept drilling on it. By the eighth follow-up I was past the rehearsed script and into the actual system, which I think was the point of the exercise.

Round 4: Bar Raiser

The bar raiser round was entirely behavioral. Six stories in sixty minutes, with deep follow-ups on three of them. The bar raiser is from a different org by design, so they had no context on my domain. They were grading raise-the-bar and a second principle I never confirmed.

The story that did the most work for me was a failure: a feature I had shipped that caused a regression we caught two days later. I told it without sanding the rough edges, including the part where the post-incident document had me down as the proximate cause. The bar raiser asked four follow-ups about what I would do differently and then moved on. I think the unsanded version is what the bar raiser wanted, though I cannot prove it.

Round 5: Hiring Manager

Forty-five minutes, mostly conversation about the team's roadmap and a couple of softer behavioral questions. This round felt the most like a normal job conversation, but my recruiter told me afterward that the hiring manager scores on two principles too.

What Tipped the Decision

The loop ended with an offer. The recruiter shared, on the offer call, that the bar raiser and round three had been the strongest, and round one had been the weakest, but no round had been below bar.

I ended up declining. The team was a good match technically but the on-call rotation was heavier than I wanted at that life-stage and the comp band did not stretch to where I needed it to. I tell the full story here because every Amazon offer write-up online ends with sign, and that is not how every loop ends.

The leadership-principles trick that changed how I prep

Memorize the leadership principles in your own words, not the official phrasing. Have a story for each, including at least three failure stories. Treat every round as having a hidden behavioral component, including the coding rounds. And do not under-prep the dive-deep prompt: shallow technical stories are the single thing that the bar raiser round in the loops I sat through was most willing to fail you on.