The Amazon SDE (Software Development Engineer) online assessment is the first technical gate in Amazon's software engineering hiring process. Pass it, and you move to phone screens and virtual onsite interviews. Fail it, and you're out—no feedback, no second chance for six months. That makes this two-hour assessment one of the most consequential tests you'll face in your tech job search.
This guide covers exactly what the Amazon SDE online assessment includes, how each section is scored, the most effective preparation strategies, and common mistakes that derail strong engineers on this specific test format.
Amazon's SDE online assessment is a proctored test administered through a third-party platform (typically HireVue or HackerRank). It's sent to candidates after an initial resume screen and before any human interview. The assessment has two main components: coding challenges and behavioral questions based on Amazon's Leadership Principles.
The total time is typically 90 to 120 minutes, divided between the coding and behavioral sections. The coding portion carries the most weight—Amazon's automated evaluation system scores your code solutions, and a low score on the coding section is almost always disqualifying regardless of your behavioral responses.
Different SDE levels (SDE I, SDE II, SDE III) may receive different difficulty calibrations, but the format is similar across levels. Senior candidates typically see harder algorithmic problems and more nuanced LP scenarios.
The coding section usually contains two or three problems of varying difficulty. Amazon uses a mix of data structure and algorithm problems that are similar to LeetCode medium and hard difficulty. Here's what typically appears:
Arrays and strings. Manipulation, sliding window, two-pointer problems. These appear frequently and test whether you can implement solutions cleanly under time pressure.
Trees and graphs. BFS, DFS, binary tree traversal, shortest path. Amazon particularly likes tree problems because they reveal whether a candidate understands recursion and can write clean recursive code.
Dynamic programming. Memoization, tabulation, classic DP patterns like longest common subsequence or coin change variants. DP problems separate candidates who can recognize subproblem structure from those who can't.
Hash maps and sets. Frequency counting, deduplication, lookup optimization. These appear in nearly every SDE assessment in some form because they're so fundamental to efficient solutions.
Your code must compile and pass test cases to score. Partial credit exists if you pass some test cases but not all, so even an incomplete solution that handles basic cases is better than no submission. Amazon tests edge cases aggressively—empty inputs, single elements, negative numbers, very large inputs—so always think through edge cases before submitting.
Practice on our Amazon coding assessment practice tests to get comfortable with the interface and question styles you'll encounter.
After the coding section, you'll face behavioral questions—sometimes written, sometimes in video format. Amazon calls these Leadership Principle questions, and they're exactly that: scenarios designed to assess how well your natural work behaviors align with Amazon's 16 LPs.
Common formats include:
Written STAR responses. You're given a prompt and asked to describe a specific situation where you demonstrated a particular behavior. Amazon wants Situation, Task, Action, Result—concrete specifics, not general statements.
Ranking scenarios. You're given a workplace situation and asked to rank a set of response options from most to least effective. These are evaluated against LP alignment, not just general professionalism.
Video questions. Some assessments include short recorded video questions where you answer on camera within a time limit (typically 90 seconds to 3 minutes). These evaluate communication clarity, not just content.
For written STAR responses, Amazon evaluates specificity and outcome orientation heavily. Vague answers—about a time you were a team player, generally—score poorly. Specific answers—about a time you identified a 23% performance regression, traced it to a specific architectural decision, proposed and shipped a fix that resolved it within two sprint cycles—score well. Our guide on how to pass the Amazon assessment covers LP alignment strategy in depth.
Some SDE online assessments include a debugging section with 7 to 10 code snippets, each containing one or more bugs you need to identify and fix. You're given 20 to 30 minutes for this section—roughly 2 to 3 minutes per problem.
Debugging questions test different skills than writing code from scratch. They require you to:
Read code quickly and identify what it's supposed to do. Find logical errors (off-by-one errors, incorrect conditionals, wrong data structure usage) and syntactic or type-related bugs. Fix the code with minimal change—Amazon doesn't want you rewriting the function, just fixing the specific bug.
Common bug types in debugging sections: off-by-one errors in loop bounds, reversed comparison operators, null/None reference issues, incorrect recursion base cases, and missing edge case handling. Practice reading code critically rather than just writing it—this is a different cognitive skill that many strong developers underestimate.
Time pressure is the silent factor that trips up many strong candidates. Here's how to approach the time allocation:
For coding problems, read both/all problems before starting. Sometimes a harder-seeming problem has a more intuitive solution. Start with the problem you feel most confident about—partial credit on two problems is better than a perfect score on one and nothing on the other.
For each coding problem: 5 minutes to understand the problem and identify the core algorithm; 15 to 25 minutes to implement a working solution; 5 minutes to test and fix edge cases. If you're still stuck after 20 minutes, implement whatever brute force approach you can—a slow solution that works beats a fast solution that doesn't compile.
For the behavioral section: plan your responses before you type. Amazon wants specific stories, not improvised rambling. A 30-second planning phase before writing saves you from submitting a vague answer you'll regret.
The candidates who pass the Amazon SDE online assessment consistently do one thing differently from those who fail: they practice the right problem types on a deadline, not just randomly browse LeetCode for months.
Here's what works:
Master the core patterns, not just individual problems. Amazon's coding problems are variations on a limited set of patterns: sliding window, two pointers, tree traversal, dynamic programming, graph search. If you understand the pattern, you can solve novel problems that use it. If you've only memorized specific problems, you'll get stuck the moment Amazon uses a twist you haven't seen.
Practice under timed conditions. Most developers are much slower under time pressure than they are when casually solving problems. Simulate exam conditions—set a 25-minute timer per problem and code in a plain IDE without autocomplete. The discomfort during practice makes the real assessment feel manageable by comparison.
Prepare LP stories before the day. Don't wing the behavioral section. Write out 5 to 6 specific work stories that can flex across multiple Leadership Principles. A story about a time you identified a significant technical debt issue and drove its resolution can cover Ownership, Insist on Highest Standards, and Deliver Results simultaneously—with different framing depending on which principle the question targets.
Our Amazon online assessment practice tests and Amazon coding assessment preparation resources give you structured practice across both the technical and behavioral components. Use them as the core of your preparation—consistent, structured practice over 1 to 2 weeks is the preparation approach that produces results.