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Amazon interview notes, page 102 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·Software Engineer·Onsite - Coding / Algorithms

Jun 2026
Amazon coding round, one question, classic graph problem. Nothing too wild but topological sort is one of those things you either remember cold or you don't.
  • Given a list of courses with prerequisites, determine if a valid course ordering exists and return the order if so.

“BFS topological sort.”

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Amazon·Software Engineer·Technical Phone Screen

Jun 2026
Amazon SWE coding round, pretty much just one algorithmic question about grid traversal. Short session, not much to say about it.
  • Given an n x n grid of 1s and 0s, return the total number of islands (connected groups of 1s).

“Classic BFS/DFS problem.”

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Amazon·Software Engineer·Online Assessment (OA)

Jun 2026
Amazon SWE assessment where you're handed a broken loan-application repo and told to fix it using an AI assistant until the test suite goes green. The known bugs are spelled out for you, but the catch is there are related edge cases lurking that nobody mentions.
  • You are given a loan-application repository with known bugs. Use an AI assistant to identify and fix them so the full test suite passes. The stated issues are: users cannot create a loan, users cannot view their existing loans, and users with insufficient balance can still fund a loan.

“The prompt hands you three bugs on a plate, which feels generous until you realize the test suite has opinions about things the prompt never mentions.”

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Amazon·Software Engineer·Technical Phone Screen

Jun 2026
Amazon coding interview, one question on string permutations. Pretty standard algorithmic problem but it has a few ways to approach it and I wasn't sure which one they wanted.
  • Write a function to generate all permutations of a given string.

“I went with recursion and backtracking, swapping characters in place.”

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Amazon·Data Scientist·Technical Phone Screen

Jun 2026
Science-breadth screen for an Amazon Applied Scientist role, basically a check on whether you know your ML fundamentals cold. Two fairly meaty topics in one question, which I wasn't quite expecting to go that deep on in a single session.
  • Walk me through how a decision tree is trained, including how split points are selected, how you control tree growth or prune it, and how you prevent overfitting.
  • Name at least three clustering algorithms and explain the core idea behind each one.

“I started with Gini vs entropy and felt pretty solid there, but when they pushed on post-pruning specifically I fumbled a bit.”

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Amazon·Data Scientist·Technical Phone Screen

Jun 2026
Amazon data scientist interview with a coding question focused on simulation and pandas. Pretty applied, felt more like a take-home task crammed into a live session. The numpy angle was a nice touch but I fumbled the timestamp logic at first.
  • Write a Python function that generates a simulated clickstream DataFrame with columns for user ID, event timestamp, page visited, and whether the user clicked. Each user should have 1 to 10 random page visits per day over a given number of days, with a 15% click probability.

“I started by sketching the loop structure mentally and immediately got tangled on the timestamp part.”

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Amazon·Software Engineer·Technical Phone Screen

Jun 2026
Amazon SWE coding round with a Python data processing problem. Pretty standard algorithmic stuff but they threw in the complexity analysis requirement which I wasn't expecting to spend much time on.
  • Given a 2D list of integers, compute the sum of squares for each sublist and return the results as a flat list. You cannot use built-in aggregation functions like sum. Also provide time and space complexity analysis.

“The core logic wasn't bad, nested loops to accumulate squares manually.”

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Amazon·Software Engineer·Onsite - System Design / Architecture

Jun 2026
Amazon system design round for a software engineer role. The whole session was basically one giant question about building a ticket selling platform, and they wanted you to go deep on pretty much every layer of the stack.
  • Design an extensible event ticket system that supports concerts, movies, and sports events. Walk through creating events, managing inventory, holding and purchasing seats with idempotency, and handling refunds.
  • How would you design the class and interface structure so that new ticket types can be added without changing existing code? Describe a factory or registration mechanism that supports this.
  • Prices need to be determined by pluggable strategies so each ticket type can have its own pricing logic, like dynamic pricing, fees, or discounts. How do you architect that?
  • How do you handle concurrency when multiple users are trying to reserve the same seat at the same time?
  • Walk through your persistence schema, how you'd handle transactions and rollbacks, and your error handling approach for this system.
  • What REST or gRPC APIs would you expose for this system? Describe the core endpoints and your reasoning.
  • How would you test this system, and how would you evolve it as new ticket types and pricing policies are introduced over time?

“This question is a lot.”

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Amazon·Software Engineer·Technical Phone Screen

Jun 2026
Amazon SWE coding round, one problem the whole session. CSV parsing with a hashmap join to compute message latency. Pretty focused and not too flashy, but the edge cases are where they really dig in.
  • Given two CSV log files (one for sent messages, one for received), compute and print the latency for every message that appears in both files. Latency is the received timestamp minus the sent timestamp. Messages that were sent but never received, or received but never sent, should be omitted from the output.

“The core of the problem is just a hashmap join keyed on (message_type, id).”

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Amazon·Software Engineer·Online Assessment (OA)

Jun 2026
Amazon SWE online assessment with a trading system optimization problem. The question had a clever constraint that made greedy approaches feel wrong at first.
  • You have a sequence of operations, each with an associated reward. No more than k identical operations can appear consecutively. You can skip operations entirely. Find the maximum total reward achievable from a valid subsequence.

“Spent way too long trying to think of this as a pure greedy problem and kept failing the example mentally.”

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