What These Interviews Are Testing
Google and Amazon interviews are among the most structured and well-documented hiring processes in the industry. They're testing specific things: algorithmic problem-solving, system design thinking, and behavioral competencies (especially Amazon's Leadership Principles). Understanding the framework makes preparation more efficient.
Google's process typically includes multiple rounds of coding, a system design round, and a "Googleyness" culture round. Amazon's includes behavioral rounds tied directly to their 16 Leadership Principles, plus technical rounds depending on the role. Both use a structured debrief process where interviewers vote on a hire/no-hire recommendation.
How Long to Prepare
For most engineers, a realistic preparation timeline is 8-12 weeks of consistent daily practice. Candidates who try to compress this into two weeks rarely perform as well. The skill being built is pattern recognition and problem-solving speed under pressure, and that takes repetition over time, not intensity over a short period.
If you're preparing for a senior role with significant system design components, add another 2-4 weeks focused specifically on distributed systems concepts.
Coding Interview Prep
LeetCode is the standard. Work through problems by category rather than randomly. The most important categories for Google/Amazon are: arrays and strings, linked lists, trees and graphs, dynamic programming, and system design (separately). Within each category, understand the pattern before trying to memorize solutions.
A reasonable target is 150-200 problems completed, with emphasis on medium and hard difficulty. Easy problems are good for warmup. Most interview problems are medium difficulty with optimizations that move toward hard.
Time yourself. Interview conditions involve a time constraint. Practice in a text editor without autocomplete. Explain your thinking aloud while you code. These conditions feel artificial at first but are important to simulate.
System Design Prep
System design questions are often the most differentiating factor for senior candidates. Common questions include designing a URL shortener, building a messaging system, designing Twitter's backend, or scaling a payments infrastructure.
Learn a framework for approaching these: clarify requirements, back-of-envelope estimation, high-level design, then deep dive on components. The key is to drive the conversation rather than waiting for prompts, and to demonstrate awareness of trade-offs at each decision point.
Resources: Alex Xu's "System Design Interview" books (Volume 1 and 2) are the most widely recommended. Supplement with case studies of how real systems are built (engineering blogs from Uber, Netflix, and LinkedIn are excellent).
Amazon's Leadership Principles
Amazon's behavioral interview is unlike anything at most other companies. Every behavioral question is mapped to one or more of their 16 Leadership Principles. Before your interview, read all 16 and prepare one to two detailed STAR stories for each one.
The principles that come up most frequently: Customer Obsession, Ownership, Bias for Action, Invent and Simplify, Are Right A Lot, Deliver Results. Having a clear, specific story for each of these is not optional at Amazon — it's the minimum preparation.
Mock Interviews Are Non-Negotiable
Practicing alone gets you to a baseline. Mock interviews with another person take you from baseline to performance-ready. The psychological experience of being watched while you solve a problem is different from solving it alone, and you need to acclimate to that pressure before the real thing.
Pramp and Interviewing.io offer free and paid mock interview options with real engineers. If you have a friend or colleague who has been through these processes, ask them to run mocks with you. Three to five mock interviews over your preparation period is a reasonable target.
What to Do the Week Before
Stop grinding new problems. Review your notes on the patterns you've studied. Do a few warmup problems daily at medium difficulty. Sleep. The week before is not the time to learn dynamic programming from scratch.
Review the company's recent engineering blog posts, product announcements, and any public statements about technical direction. This signals genuine interest and gives you material for the "why this company" question.