Big Tech Interview Preparation Timeline: Complete Checklist from 3 Months Out to Interview Day

Background: How I Spent 3 Months Preparing for FAANG Interviews from Scratch

A year ago, I was a mid-level backend developer at a mid-size company, dreaming about breaking into FAANG but dreading every LeetCode session and falling asleep over system design books. Then I read a post that said "interview prep is a marathon, not a sprint," and I realized I didn't lack effort—I lacked a clear timeline and an actionable checklist. So I started 3 months out, phased my preparation, and eventually landed offers from Meta, Google, and Amazon. This article is my complete breakdown of the 5-phase process, and I hope it helps you too.

Detailed Breakdown: Task Checklists for All 5 Phases

Phase 1: 3 Months Out — LeetCode + Fundamentals (Laying the Foundation)

This phase is the most painful but also the most important. I set a hard target: at least 150 Medium problems, covering arrays, linked lists, trees, dynamic programming, graphs, backtracking, and greedy algorithms—7 major categories. I did 2-3 problems daily and batch-reviewed on weekends. Grinding isn't just about finishing; I annotated each problem: did I come up with the approach independently, is there a better solution, which template does it belong to?

For fundamentals, I reviewed operating systems, computer networking, databases, and algorithms & data structures—4 major modules, about 1 week each. The key wasn't memorization but understanding principles well enough to explain them in my own words. For example, with TCP's three-way handshake, I didn't just memorize the steps—I asked "why not two? What happens if the third packet is lost?"

Detailed Task Checklist:

1. Create a daily problem schedule: 2 on weekdays, 5 + weekly review on weekends, 150 Medium in 12 weeks

2. Solve problems by category—minimum 15 per type, 20 each for DP and graphs

3. Build a mistake log: record problems that stumped you and key insights

4. Operating Systems: processes & threads, memory management, deadlocks, scheduling algorithms

5. Computer Networking: TCP/UDP, HTTP/HTTPS, DNS, congestion control

6. Databases: indexing, transaction isolation levels, locking, SQL optimization

7. Write 1 fundamentals note per week, restating core concepts in your own words

Phase 2: 2 Months Out — Project Prep + System Design (Building the Frame)

LeetCode and fundamentals are the baseline, but what really differentiates candidates at FAANG is project depth and system design ability. I spent a lot of time restructuring every project on my resume using the STAR method: Situation (project context and challenges), Task (my specific responsibilities), Action (key decisions I made), Result (quantified outcomes—e.g., 40% QPS improvement, 60% latency reduction).

For system design, I practiced 2 classic problems per week—design Twitter, design a URL shortener, design a flash-sale system, design a message queue. For each one I followed the flow "requirements analysis → capacity estimation → high-level design → detailed design → extended discussion," and I always drew architecture diagrams, even if just rough sketches.

Detailed Task Checklist:

1. Restructure each resume project with STAR; identify 3-5 deep-dive technical points per project

2. Prepare "elevator pitch" versions of 2-3 projects—1 minute to explain what you did and what problem you solved

3. System design: 2 problems per week, 8-10 classic problems total

4. Draw architecture diagrams for each system design problem, labeling key components and data flows

5. Practice capacity estimation: QPS, storage, bandwidth calculations

6. Prepare behavioral questions: most challenging project, handling team conflict, lessons from failure

7. Research target companies' business characteristics and tech stack preferences

Phase 3: 1 Month Out — Mock Interviews + Gap Filling (Finishing Touches)

The core of this phase is performing under real pressure. I found 5 friends and former colleagues to act as mock interviewers, covering algorithms, system design, and project deep-dives. My first mock was a disaster—hands shaking, 40 minutes on a Medium problem with no working solution. But that exposure accelerated my progress. By the 5th mock, I could consistently produce optimal solutions in under 20 minutes.

For gap filling, I revisited my mistake log and weak spots from the first two phases. I focused especially on topics I'd "seen but couldn't explain clearly"—like Redis persistence mechanisms or MySQL's MVCC. I also started preparing salary negotiation strategies, researching compensation bands for target companies and levels.

Detailed Task Checklist:

1. Complete at least 5 full mock interviews, 45-60 minutes each

2. Debrief after every mock: which problems stumped you, was your communication clear, was time well-managed

3. Target weak problem types with 20-30 focused practice problems

4. Practice whiteboard coding: write code on paper or a whiteboard without an IDE

5. Review mistake log and fundamentals notes until core concepts roll off the tongue

6. Research target company salary bands; prepare a 3-tier offer strategy

7. Prepare 3-5 high-quality questions for "Do you have any questions for us?"

Phase 4: 1 Week Out — Mindset Adjustment + Equipment Check (Pre-Move Inspection)

In the final week, do not learn anything new. My biggest mistake in my first FAANG prep was cramming new system design problems the day before—I got more anxious and blanked during the interview. I learned my lesson: the last week is for only three things—review notes, test equipment, and stabilize mindset.

Reviewing notes means quickly going through the mistake log and STAR project outlines to keep them fresh. Testing equipment includes camera, microphone, lighting, and network—virtual interview details that directly affect first impressions. For mindset, I did things that helped me relax: running, watching shows, and ensuring 7-8 hours of sleep every night.

Detailed Task Checklist:

1. Quickly review mistake log and core notes—no new content

2. Test camera, microphone, and lighting; ensure clear video and audio

3. Check network stability; prepare a mobile hotspot as backup

4. Lay out interview outfit—virtual interviews: professional top half, neat overall

5. Ensure 7-8 hours of sleep nightly; no late nights 2 days before the interview

6. Prepare water, pen and paper, printed copies of your resume for interview day

7. Do one full mock interview as a warm-up to stay sharp

Phase 5: Interview Day — Key Reminders (Handing Over the Keys)

Your state on interview day determines whether 3 months of preparation translates into actual performance. My principles: arrive early, backup equipment, stay calm, take notes. For virtual interviews, join the meeting 15 minutes early and check audio/video; for in-person, arrive 20 minutes early and get comfortable. If you hit a problem you can't solve, don't panic—talk through your approach first. Interviewers often care more about your thought process than a perfect answer.

After each round, I immediately wrote down the questions asked and my responses—useful for debriefing and preparing for the next round. If you have multiple rounds in one day, don't scroll through other people's interview reports during breaks. Just drink water and breathe.

Detailed Task Checklist:

1. Virtual: join 15 minutes early. In-person: arrive 20 minutes early

2. Prepare backup equipment: spare headphones, charger, mobile hotspot

3. If stuck, explain your thinking before coding—show your problem-solving process

4. After each round, immediately record questions and key response points

5. Between rounds: no browsing interview tips—hydrate and breathe

6. Send a thank-you note after the interview, expressing enthusiasm for the role

7. Do a full debrief after all interviews to build experience for the next one

Real Problems: High-Frequency Questions I Encountered

Below are problems I actually faced or saw frequently mentioned in Meta, Google, and Amazon interviews, organized by type:

Algorithms: LeetCode 3 (Longest Substring Without Repeating Characters), LeetCode 15 (3Sum), LeetCode 200 (Number of Islands), LeetCode 121 (Best Time to Buy and Sell Stock), LeetCode 146 (LRU Cache), LeetCode 215 (Kth Largest Element in an Array), LeetCode 72 (Edit Distance), LeetCode 42 (Trapping Rain Water)

System Design: Design a URL shortener, Design a news feed, Design a flash-sale system, Design an instant messenger, Design a distributed ID generator

Fundamentals: TCP three-way handshake and four-way teardown, MySQL indexing and optimization, Redis cache penetration/breakdown/avalanche, inter-process communication, virtual memory and page replacement, HTTP/2 vs HTTP/3, CAP theorem and BASE principles

Key Takeaways: 3 Pieces of Advice from Someone Who's Been There

First, don't wait for perfection to start. I've seen too many people say "I'll apply after I finish 300 problems"—then grind for 6 months without a single interview. 150 Medium problems + solid fundamentals are enough for most FAANG first rounds. Get the interview first, then keep growing through the process.

Second, mock interviews matter more than grinding problems. Grinding is practicing in your comfort zone; mock interviews are performing under pressure. If you can only do one thing to improve your interview performance, find someone to mock interview with.

Third, interviewing is a two-way street—don't beg for the job. FAANG companies have great reputations, but that doesn't mean you should abandon your own judgment. Observe the team culture, whether the tech stack fits, and how much room there is to grow. When you have multiple offers, choose the one that excites you—not just the most famous name.

FAQ: Common Questions Answered

Q: Is 3 months enough prep time? A: For developers with 1-3 years of experience, 3 months of full-time prep is sufficient. If you're switching from zero, plan for at least 6 months. If prepping while working, 2-3 hours daily for 3 months works, but you must stick to the plan strictly.

Q: Which matters more—LeetCode or fundamentals? A: Both matter, but priorities depend on the target company. Meta emphasizes algorithms, Amazon values leadership principles and behavioral depth, Google is relatively balanced. Start with LeetCode, then adjust focus based on your targets.

Q: How do I prepare for system design with no real experience? A: No real experience doesn't mean you can't prepare. Learn the methodology first (requirements → estimation → high-level → detailed → extensions), then accumulate material through tech blogs and open-source projects. Practice 8-10 classic problems like designing Twitter or a URL shortener, and you'll have the framework down.

Q: What if I can't find anyone for mock interviews? A: You can do peer mocks with friends in the industry, or use platforms like Pramp and Interviewing.io to practice with strangers. If all else fails, record yourself on camera and review the playback—you'll catch many communication issues you wouldn't notice otherwise.

Q: What if I'm too nervous on interview day? A: Nerves are normal—they mean you care. My trick: take 5 deep breaths before the interview and tell yourself "I've prepared for 3 months; I've done what I can." If you blank mid-interview, say "Give me 30 seconds to think through the approach"—interviewers won't mind.