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Technical Interview Guide

Welcome to InterviewStack — a free, comprehensive guide to landing your next software engineering role. Whether you're targeting FAANG, a high-growth startup, or your first engineering job, this guide has everything you need.

What This Guide Covers​

SectionTopics
🧠 Behavioral InterviewSTAR method, 50+ questions with sample answers, leadership stories
🏗️ System DesignDesign Twitter, Netflix, WhatsApp, Uber — Grokking-style real systems
⚡ Algorithms & LeetCode15 core patterns, 150+ problems, DP, graphs, trees
🟨 JavaScriptClosures, event loop, promises, prototypes, common interview questions
🤖 AI & AgentsClaude Code, MCP, building with the Claude API, agentic workflows
⌨️ Code PlaygroundInteractive JavaScript editor in your browser

The Interview Process at Top Tech Companies​

Understanding the interview structure is step one. Here's what a typical senior engineer loop looks like:

Stage 1: Resume & Application​

  • Goal: Get a recruiter call
  • Tips: Quantify impact ("reduced latency by 40%"), tailor to JD keywords, remove old/irrelevant experience
  • Referrals dramatically increase your chances — always reach out to someone at the company first

Stage 2: Recruiter Screen (30 min)​

  • Brief background discussion
  • Level calibration (are you applying for the right level?)
  • Compensation expectations
  • Tip: Be enthusiastic and researched. Know what the company does and why you want to join.

Stage 3: Hiring Manager Screen (45-60 min)​

  • Deep dive into your experience
  • Past project discussions
  • "Tell me about a time..." behavioral questions
  • Technical background discussion
  • Tip: Prepare 5-8 STAR stories covering leadership, failure, conflict, and achievement.

Stage 4: Technical Phone Screen (45-60 min)​

  • 1-2 LeetCode-style coding problems
  • Usually medium difficulty
  • May include a system design component for senior roles
  • Tip: Think out loud throughout. Interviewers care about your process, not just the answer.

Stage 5: On-Site / Virtual Interviews (4-6 hours)​

Coding rounds (2-3 rounds):

  • 45-60 min each
  • LeetCode medium/hard problems
  • Some companies ask debugging or code review questions
  • Senior+ interviews often have design components

System design round (1-2 rounds):

  • Design a real system from scratch (Twitter, Netflix, Uber, etc.)
  • Focus: requirements gathering, estimation, high-level design, deep dives
  • 45-60 min each

Behavioral round (1 round):

  • Leadership, conflict resolution, ownership stories
  • At Amazon: explicitly mapped to Leadership Principles

Bar raiser / Calibration round (some companies):

  • Senior person who has veto power
  • Focuses on culture fit and raising the bar

Stage 6: Debrief & Offer​

  • Hiring committee reviews all feedback
  • Calibration meeting determines level and offer
  • Negotiations: always negotiate — it's expected

How to Prepare Strategically​

The 4-Week Plan​

Week 1: Fundamentals

  • Review data structures: arrays, hash maps, trees, graphs, heaps
  • Practice 1 easy LeetCode problem per day
  • Review JavaScript fundamentals (if frontend/full-stack role)

Week 2: Patterns

  • Study the 15 core algorithm patterns
  • Practice 1 medium LeetCode problem per day
  • Start prepping behavioral stories using STAR

Week 3: Systems

  • Study system design fundamentals (caching, databases, load balancing)
  • Design 2-3 systems end-to-end (URL shortener, Twitter, etc.)
  • Practice explaining your designs out loud (record yourself)

Week 4: Integration & Mock Interviews

  • Do 2-3 mock coding interviews (Pramp, Interviewing.io, peers)
  • Do 1-2 mock system design interviews
  • Refine behavioral stories, time them to 2-3 minutes each
  • Research the company deeply

Daily Habits​

  • LeetCode: 1 problem/day minimum, track patterns not just solutions
  • Review: After each problem, understand the time/space complexity
  • System design: Read 1 new architecture article or case study per week
  • Communication: Practice explaining solutions to a rubber duck (or a person)

Mindset​

Interviews measure interview performance, not engineering ability. But they're a learnable skill.

What interviewers are actually evaluating:

  1. Problem-solving ability — Can you break down ambiguous problems?
  2. Communication — Can you explain your thought process clearly?
  3. Technical depth — Do you have solid fundamentals?
  4. Coachability — Do you respond well to hints and corrections?
  5. Culture fit — Would this person be enjoyable to work with?

The biggest mistakes:

  • Jumping to code before fully understanding the problem
  • Silence — interviewers can't help you if they don't know where you're stuck
  • Giving up when stuck — show your partial thinking process
  • Not testing your solution with examples
  • Optimizing prematurely

Getting Started​

Pick your weakest area and start there. If you're strong in algorithms but haven't done system design — start with System Design. If behavioral interviews make you nervous — start with the STAR Method.

Consistent practice beats marathon sessions. 1-2 hours per day, every day, for 4-6 weeks will get you ready for most interview loops.

Good luck! You've got this. 🚀

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