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Hello folks, are you preparing for coding interviews but not sure where to start? Are you drowned in the sea of Data structures and algorithms, and System design, and whatnot, then you have come to the right place.
Earlier, I shared 11 best System Design Interview resources, and in this article, I will share with you a systematic approach to prepare for coding interviews and also cover all the bases.
Looking for a job in this tough market is not easy, as many people are looking for jobs and the market is flooded with a lot of talented people, thanks to what his happening in the world.
But that should not be an excuse; you also need to level up yourself to stand a chance.
Here are things you can do on your side for rock-solid preparation.
By the way, if you are looking for a stop shop to prepare for a coding interview, then the DesignGurus.iois a great place to start with.
They have many Grokking courses to prepare for coding interviews like OOP Design, System Design, Dynamic Programming, etc, and you can get access to all of their courses for a big discount by joining their All course bundle. You can also use code GURU to get 30% discount.
How to Prepare for Coding Interviews in 2025?
Here is your step-by-step guide to prepare well and crack the coding interviews and covering all the topics that matter:
1. Data Structures and Algorithms
If you're serious about coding interviews in 2025, nailing DSA is non-negotiable. Here are the best resources to kick off your prep, whether you're brushing up or starting from scratch:
1. AlgoMonster
A streamlined, interactive platform designed by Google and Facebook engineers. It helps you learn coding patterns fast, with visual explanations and no fluff. Great for busy professionals.
2. Educative's 99 Coding Patterns
Available in both Python and Java, this course covers 26 essential patterns you'll see again and again in interviews. The interactive, code-in-browser format makes it easy to practice and internalize concepts.
3. Blind 75 (Free)
This is a classic, no-nonsense list of 75 must-solve problems. If you're short on time, these are the problems you don't want to skip. It's widely recommended by engineers who've landed jobs at FAANG companies.
4. Grind 75 (Free)
Created by a former Meta engineer, Grind 75 builds on Blind 75 with a better structure. It provides a 4- to 8-week plan tailored to how much time you have per day, making it easier to stay on track.
5. Practice C++ STL, Java Collections, or Python's built-in data structures\
Speed matters in interviews. Make sure you're fluent with your language's standard libraries so you can code efficiently under pressure. The right API knowledge can save precious minutes during your interview.
If you are a beginner, DSA requires more than 3 months of active practice. I am omitting the details in this post, but if you are rusty, start with the top interview questions and coding interview patterns on sites like LeetCode and AlgoMonster.
Here is also a nice coding interview patterns cheat sheet from Educative.io, which shows which coding problems can be solved with which coding patterns
2. System Design
When it comes to system design interviews, passive learning won't cut it. Here's how to build a solid foundation and sharpen your skills:
1. System Design Interview books by Alex Xu (Volumes 1 & 2)
These are the gold standard for system design prep. The books break down real interview questions and walk you through design trade-offs and scaling strategies. If you prefer online learning, the ByteByteGo course offers digital content of both books and a few more complementary materials.
2. Best YouTube Channels for System Design
If you're more of a visual learner, these channels cover key system design concepts with diagrams and real-world examples. They're perfect for quick refreshers or deep dives into tricky topics.
3. Solve problems actively, not just read about them
It's tempting to read solutions and move on. Don't. Sketch out designs, write down trade-offs, and think through failure points as if you're in the interview room.
4. Mock interviews on Pramp and Exponent
Practice live with peers or coaches. You'll get real-time feedback and experience thinking on your feet, which is critical for design interviews.
5. Codemia.io System Design practice in LeetCode style
Passive learning won't help much here. Codemia.io lets you practice system design problems just like you'd practice coding questions. It's one of the few platforms built specifically for this, and they also have the biggest collection of System design problems.
3. Low-Level Design (LLD)
If your LLD skills are rusty, don't worry. The key is to combine the right resources with deliberate, hands-on practice.
1. Design Principles:
Start with the classic "Head First Design Patterns" (2nd edition). This book explains core design patterns through simple, practical examples. It's approachable even if you're revisiting the material after a long gap.
2. Object-Oriented Design Interview: An Insider's Guide
Co-authored by Desmond Zhou, Fawaz Bokhari, and Alex Xu, this is one of the most up-to-date books on OOD interviews. It offers a no-nonsense 4-step framework for solving design problems, 11 detailed examples, and 133 diagrams that break down architectures and workflows. It's exactly what you need to bridge the gap between theory and interview-ready skills.
3. OOP concepts must be crystal clear.
Brush up on fundamentals like virtual methods in C++, abstract classes vs interfaces, method overloading vs overriding, and method hiding. These are the building blocks that interviewers expect you to know cold.
4. Practice real questions:
Check out Awesome Low-Level Design by Ashish Pratap Singh. It's a curated list of top-notch LLD problems that'll push you to think critically. I highly recommend subscribing to his AlgoMaster newsletter for ongoing tips.
5. Put yourself on the clock:
When practicing, timebox each design problem to 45 minutes. Simulating interview pressure helps you focus and sharpen your decision-making.
6. Study detailed solutions:
Explore this Low-Level Design playlist (credits to Soumyajit Bhattacharyay). Walk through the solutions only after you've made your own attempt---don't short-circuit the learning.
4. CS Fundamentals
Many candidates overlook computer science fundamentals in interview prep, but this is where a lot of interview questions are rooted. Brushing up on these topics helps you not only crack tough technical rounds but also build confidence when explaining concepts under pressure.
1. Core CS concepts:
Start with GateSmashers. Their free YouTube playlists cover subjects like data structures, algorithms, operating systems, DBMS, computer networks, and OOP. The explanations are beginner-friendly but thorough enough to refresh what you learned in school.
2. Operating systems:
OS concepts frequently come up in interviews at top tech companies. Make sure you understand process management, memory allocation, deadlocks, threading, file systems, and scheduling.
If you're looking for structured material, check out these 6 best operating system courses. They range from beginner to advanced and include both video lectures and interactive exercises.
3. Additional fundamentals to cover:
Don't stop at OS. Spend time on computer networks (especially HTTP, TCP/IP, WebSockets), database indexing, transactions, and basic compiler concepts. These areas pop up in systems design and low-level design discussions more often than you'd expect.
4. How to study effectively:
Treat CS fundamentals like system design: don't just read or watch. Take notes, draw diagrams, and explain concepts out loud. Mock interviews often test how well you can articulate these ideas, not just how well you understand them internally.
Here is another nice computer science fundamentals cheatsheet from Educative.io for quickly refreshing essential points
5. Behavioral
Many candidates underestimate the weight behavioral interviews carry. The truth is, no matter how strong your coding or system design skills are, you won't clear the hiring bar without showing strong communication, teamwork, and problem-solving under real-world pressures.
1. Structure with the STAR method (Situation, Task, Action, Result).
This isn't optional. STAR helps you present your experiences clearly and logically. Interviewers don't want rambling stories---they want to see how you handled challenges, made decisions, and measured success.
2. Keep your responses tight.
Each example should fit into 4-5 sentences per section of STAR. The goal is to respect the interviewer's time and stay focused. Brevity shows clarity of thought and respect for the conversation flow.
3. Prepare both long and short versions of your stories.
Sometimes, interviewers want a quick overview. Other times, they'll probe deep. Have both versions ready so you can adapt on the fly. This makes you sound polished and confident, not like you're reciting memorized lines.
4. Don't neglect preparation.
Behavioral rounds can be deceptively tricky. You'll face questions about failure, conflict, leadership, ambiguity, and ethics. The Grokking the Behavioral Interview course on Educative is a solid, free starting point. It provides frameworks, examples, and sample answers that can help you build and polish your own stories.
5. Pro tip: Practice out loud.
Writing down your answers is good. Saying them out loud is essential. Record yourself, review how you sound, and refine. You'll be surprised how much smoother your answers become with just a few rounds of self-review.
6. Company-specific Preparation
Generic prep will only take you so far. Once you've covered your bases with data structures, algorithms, system design, and CS fundamentals, it's time to shift gears and focus on company-specific patterns.
Each company has its quirks, preferred question types, and even favored topics. Tailoring your prep shows you're serious about the role.
1. Use LeetCode Premium, AlgoMonster, or Codemia.io for targeted practice.\
AlgoMonster, Codemia.io, and LeetCode Premium's biggest advantage is their massive bank of company-tagged problems.
You can filter questions asked by companies like Google, Amazon, Microsoft, or startups. Focus on problems that were asked in the past 6- 12 months, as they reflect current trends in hiring.
2. Dive into the Explore tab on LeetCode.
The Explore tab in LeetCode Premium offers guided learning paths that cover everything from data structures to dynamic programming.
What's great is that these paths are structured to build skills progressively. Use these when you want a break from random problem grinding and prefer a curriculum-style approach.
3. Simulate the real interview using the LeetCode Interview tab.
Head over to LeetCode's Interview tab. This lets you select a company, choose the interview round (phone, onsite, etc.), and attempt a timed assessment that mirrors the actual interview experience.
It's a brilliant way to get into the mindset of solving problems under time pressure and see how you'd perform on the big day.
4. Don't stop at LeetCode.
Explore company-specific forums on Glassdoor, Blind, or TeamBlind to read about recent interview experiences.
Many candidates share exact question patterns and system design prompts they encountered. You'll spot trends that can give you an edge.
5. Final tip: Mimic the real setting.
When practicing, sit down with a whiteboard or plain text editor, no autocomplete, no IDE. Set a timer and solve problems as if you're in an interview. The more realistic your practice, the calmer you'll be when it counts.
For coding interview patterns, I also recommend this new book called Coding Interview Patterns: Nail Your Next Coding Interview, particularly for those who love reading books like me
That's all about how to prepare for coding interviews in 2025. I know it's not easy to cracka coding interview in this tough market, but following this guide and preparing for all the important topics mentioned in this article can improve your chances a lot.
You can also start with the Educative-99**, for a structured preparation. Here, you will have the opportunity to solve 99 carefully selected questions, rather than 2,800 Leetcode problems. This will also help you master the above coding patterns more effectively.
By the way, I have shared best data structure interview books and software engineering books, best System design books and courses, if you haven't checked them yet then you can also see them for coding interview prep and also covering all the bases.
I hope these tips help you in your preparation. Feel free to reach out if you have any questions or need guidance.
Good luck to everyone on their journey!
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