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Amazon interview notes, page 130 of 159

FAANG / Big Tech

Most of these Amazon write-ups come from Software Engineers (1,092), then Data Scientists (182) and Product Managers (165). The most reported rounds are the technical phone screen (618), the behavioral / leadership round (309), the online assessment (228) and the system design round (159).

1581 interview notes · updated Oct 2026

Amazon·Product Manager·Onsite - Product Sense / Strategy

Jun 2026
Amazon PM interview with a classic homepage recommendation engine design question. Pretty open-ended, which I wasn't fully prepared for.
  • How would you design the recommendation engine for Amazon's homepage?

“I jumped straight into personalization and collaborative filtering before even asking what problem we were trying to solve.”

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Amazon·Software Engineer·Onsite - System Design / Architecture

Jun 2026
Amazon SWE interview with two design-heavy questions back to back. The OOP one felt manageable but the scalable bookstore question had a lot of moving parts and I wasn't sure how deep to go on the architecture side.
  • Design object-oriented classes for a document and tag system that supports thread-safe operations across multiple concurrent threads.
  • Design a scalable online bookstore system that handles both browsing and purchasing workflows.

“Spent the first few minutes just sketching out the class hierarchy before even thinking about concurrency.”

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Amazon·Software Engineer·Onsite - System Design / Architecture

Jun 2026
System design round at Amazon for a software engineering role, focused entirely on building a ride-hailing matching system. The whole session was basically one giant design problem with a lot of sub-parts, which felt manageable until the follow-ups started stacking up.
  • Design a ride-hailing matching system like Uber or Lyft, covering GPS ingestion, nearby-driver lookup, and the full pipeline from driver location update to rider match.
  • Drivers are sending GPS updates every one to four seconds across a hundred thousand vehicles. How do you handle that write volume without overwhelming your matching store?
  • How do you deduplicate or filter out noisy, redundant, or out-of-order GPS updates from drivers?
  • How do you protect downstream services from sudden write bursts in GPS traffic?
  • A rider requests a pickup. Walk me through how you efficiently find nearby available drivers and match one to the rider.
  • Compare Quadtree and H3 hexagonal grid as geospatial indexing approaches for this system. Which would you recommend and why?
  • How does Redis GEO fit into this architecture, and how do you prevent two riders from being matched to the same driver at the same time?
  • A driver is sitting right on a cell or shard boundary. How do you make sure they aren't missed when a rider nearby requests a pickup?
  • The Redis location-index cluster for a city goes down or restarts cold. How do you rebuild the index and what does the user experience look like during recovery?

“This was the anchor question for the whole session.”

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Amazon·Software Engineer·Technical Phone Screen

Jun 2026
Amazon SWE coding round, pretty standard graph traversal territory. The question had a few layers to it so it wasn't just 'write BFS and leave', they wanted to see you think through complexity and edge cases too.
  • Given a 2D grid of 0s and 1s, count the number of connected regions made up of 1s. Cells connect in four directions. Walk through both a recursive and an iterative solution, explain how you prevent revisiting cells, and discuss time and space complexity. Handle edge cases like empty grids or very large inputs.

“I started with the recursive DFS and it went fine, but when they asked me to do the stack-based version I fumbled a bit on the order I was pushing neighbors.”

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Amazon·Software Engineer·Online Assessment (OA)

Jun 2026
Amazon OA for a SWE role, one problem involving wildcards in a binary string and counting subsequence pairs to maximize a weighted error score. Tricky modular arithmetic involved and the constraints weren't even given, which was a bit annoying.
  • You're given a string of '0', '1', and '!' characters. Replace each '!' with either '0' or '1'. For the resulting binary string, count all index pairs (i < j) where s[i]='1' and s[j]='0' (call this count10) and pairs where s[i]='0' and s[j]='1' (call this count01). The total error is x * count10 + y * count01. Choose replacements to maximize this total and return it modulo 1,000,000,007.

“I spent a good chunk of time just figuring out what the problem was actually asking because subsequence pairs vs subarrays is a distinction that bites you if you skim.”

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Amazon·Data Scientist·Technical Phone Screen

Jun 2026
Amazon DS interview focused almost entirely on A/B testing, and it went deep fast. Five sub-questions all hanging off one scenario about a signup funnel. Walked out not totally sure how I did.
  • Given a baseline conversion rate of 4.0% and a minimum detectable effect of 0.4 percentage points, what sample size per arm do you need for a two-proportion z-test at 80% power and 5% significance? Show your formula and the numeric result.
  • You observe control at 4.30% (n=50,000) and treatment at 4.22% (n=49,500). Compute the p-value using both pooled and unpooled variance, build a 95% confidence interval for the difference, and explain what the result means practically.
  • How would you define primary versus guardrail metrics for this experiment, and what multiple comparison correction would you apply if you're also tracking cancellation rate and latency as guardrails?
  • Walk me through how CUPED or pre-experiment stratification reduces variance in an A/B test, and what effect that has on required sample size.
  • What are the risks of peeking at results before an experiment ends, and how do you control type-I error inflation? Also, what do you do when a global average looks flat but segment-level results show opposite directions?

“I knew the formula well enough but fumbled the plugging-in part under pressure.”

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Amazon·Software Engineer·Onsite - Behavioral / Leadership

Jun 2026
Amazon software engineering interview with a scenario-based question about handling a race condition and deciding how to communicate it to the team. Pretty situational, less about coding and more about judgment.
  • You've discovered a race condition in the codebase close to a deadline. What do you do next, and how do you communicate this to your team lead?

“The scenario wanted you to pick between a few options: loop in your lead with context and ask for guidance, set up a meeting with another teammate, keep grinding alone until the next team sync, revert the code, or just flag that the deadline is at risk.”

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Amazon·Software Engineer·Onsite - Behavioral / Leadership

Jun 2026
Behavioral round at Amazon for a software engineering role, just one question but they really sat in it with you for a while.
  • Tell me about a significant disagreement you had with someone at work. How did you make your case, how did you hear them out, and how did it get resolved?

“This question sounds simple but they kept digging.”

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Amazon·Machine Learning Engineer·Onsite - Coding / Algorithms

Jun 2026
Amazon ML Engineer loop had at least one coding/design round that was way heavier on systems thinking than I expected. The main problem was an inventory and backorder simulation, and they kept pushing on complexity and extensions.
  • Design and implement a function that processes an event stream for an e-commerce marketplace. You're given an initial inventory (SKU, quantity pairs) and a sequence of timestamped events that are either Orders or Restocks. Orders should be fulfilled from current stock; if stock is insufficient, fulfill what you can and record the rest as a backorder. Restocks should first satisfy outstanding backorders in FIFO order before adding to on-hand inventory. Return per-order fulfillment details and the final inventory state.
  • What data structures would you use for this inventory and backorder system, and what is the time and space complexity of your approach? Target O(E log S) time and O(S + B) space.
  • How would you extend this system to support order cancellation in O(log S) time?

“This took me a while to even fully parse.”

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Amazon·Software Engineer·Hiring Manager Screen

Jun 2026
Interviewed for a business analyst role at Amazon, and the focus was squarely on how you think about metrics from an executive perspective. Pretty standard for Amazon but the question has more depth than it looks.
  • How do you decide which metrics matter most for executives to keep an eye on?

“I went straight to talking about business goals and working backwards, which felt right in the moment but I think I skipped over the part about what executives actually need versus what analysts care about.”

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