Preparing for System Design Interviews Alongside Coding Interview Prep

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Preparing for tech interviews often means juggling two critical skill sets: coding and system design.

Many candidates focus heavily on coding problems but then feel overwhelmed by system design questions. Balancing both is essential for a well-rounded preparation.

This guide will show you how to prepare for system design interviews alongside coding interview prep in a structured way.

Understanding the Importance of Both Coding and System Design Skills

Both coding and system design interviews evaluate different abilities, and you can’t afford to ignore either.

Companies use coding interviews to test your algorithmic thinking and problem-solving with code, while system design interviews assess your ability to architect large-scale systems.

In other words, coding interviews focus on solving algorithmic problems, whereas system design interviews involve designing scalable, reliable systems.

Why are both important? Consider that as a software engineer you need to write efficient code and design robust systems. Strong coding skills demonstrate you can tackle data structure and algorithm challenges. System design skills show you can see the big picture – how components fit together, how to handle scale, reliability, and maintainability. Modern tech roles, even at entry-level, increasingly value candidates who have both sets of skills.

Coding Interviews: These test your knowledge of data structures, algorithms, and your ability to write correct, optimized code under pressure. It’s about solving well-defined problems quickly.
System Design Interviews: These evaluate your architectural thinking. You’ll be asked open-ended questions like how to design a scalable web service. You must outline the components (APIs, databases, caching, etc.), consider trade-offs, and communicate your design clearly.

Mastering both not only helps you pass interviews but also makes you a stronger engineer overall. A candidate who can code and design systems stands out as versatile and prepared for real-world challenges.

How to Balance Coding and System Design Prep

Balancing preparation for coding and system design interviews requires a strategic approach.

Rather than tackling one and postponing the other, integrate both into your study routine. Here’s how you can maintain a healthy balance:

Allocate Dedicated Time Slots: Split your weekly schedule between coding practice and system design study. For example, devote weekdays to coding problems (e.g. one or two problems daily) and set aside a weekend session for system design. Consistency in both areas is key.
Alternate Focus: If spending a long session on one topic drains you, try alternating – one day focused on coding, the next on system design. This keeps your prep well-rounded and reduces burnout.
Leverage Overlap: Occasionally, apply coding to system design. For instance, after designing a component (like a caching system), write a short script or outline pseudo-code to simulate its behavior. This reinforces both practical coding and design understanding.
Prioritize Your Weakness: If you’re stronger in coding, slightly increase your system design study time (and vice versa). But don’t completely neglect the other area. As one expert guide emphasizes, “Don’t neglect system design questions” during your prep (How can I spend time preparing for coding interview while working as a full time software engineer?) – even if algorithms are your main focus. The reverse is also true.
Use a Structured Approach: Approach both types of prep with a plan. For coding, follow a problem-solving framework (understand problem, brainstorm, code, test). For system design, use a clear template (gather requirements, outline high-level design, dive into components, discuss trade-offs). Having a repeatable framework for each will keep your practice sessions efficient and balanced.

By treating system design prep with the same rigor as coding (and vice versa), you ensure steady progress in both domains. Balancing isn’t about splitting time 50/50 every single day, but about making sure neither aspect is ignored over the course of your preparation period.

Structured Study Plan for Beginners

If you’re starting out, follow this step-by-step study plan to cover both coding and system design systematically:

Lay the Foundations (Week 1-2): Begin with the basics. Refresh core data structures and algorithms (arrays, linked lists, trees, graphs, sorting, etc.) and understand fundamental system design concepts. System fundamentals include learning about web architecture, databases (SQL vs NoSQL), caching, load balancing, and other scalability basics. This foundation will make advanced topics easier to grasp.
Daily Coding Practice (Ongoing): Make coding practice a daily habit. Solve problems on platforms like LeetCode or HackerRank focusing on one topic at a time (e.g., one day do array problems, next day trees). Start with easy problems and gradually move to medium and hard ones. This consistent practice builds your problem-solving speed and confidence. Aim to implement solutions from scratch and learn to optimize them. Learn how to smartly prep for coding interview.
Weekly System Design Sessions: Introduce a dedicated session each week for system design. In these sessions, pick a common system design scenario (design a URL shortener, a chat application, a file storage service, etc.) and outline a design on paper or whiteboard. Practice the standard steps: clarify requirements (functional and non-functional), propose a high-level design, identify key components (clients, servers, databases, etc.), and discuss how data flows. Don’t worry about getting the perfect design – focus on covering the main points and explaining your reasoning.
Learn in Layers: Tackle system design in layers over the weeks. For example, in early sessions concentrate on high-level architecture and making sure you cover all components. In later sessions, dive deeper into specific aspects (like database sharding, caching strategies, specific technologies). Similarly for coding, initially focus on getting solutions correct, then work on improving efficiency and recognizing patterns in problems.
Integrate and Iterate (Week 3 onward): By week 3 or so, you should be doing both daily coding and weekly design. Continuously iterate on this plan. If you find a certain topic challenging (say, dynamic programming or understanding CAP theorem in system design), allocate extra time to revisit and reinforce that area. Adjust your plan as needed, but keep both threads (coding and design) moving forward.
Mock Interviews and Feedback (After 4-6 Weeks): Once you have a base in both, start doing mock interviews. You can practice with a friend or use online mock interview platforms like DesignGurus.io. Do a 45-minute coding interview simulation and a separate 1-hour system design interview simulation. Treat them like real interviews: time-bound and pressure realistic. After each, seek feedback. Identify where you struggled – was it coming up with an optimal algorithm faster, or structuring the system design answer? Use that feedback to guide further study (e.g., practice more graph problems or review how to design a specific component).

Learn the System Design Fundamentals.

This structured plan ensures that a beginner covers both areas in parallel. It starts with fundamentals, introduces consistent practice, and ramps up to simulate real interview conditions. By following these steps, you’ll gradually build confidence in tackling both coding puzzles and open-ended design questions.

Recommended Resources for Coding and System Design Prep

Quality resources can make your preparation more effective.

Here are some highly recommended resources for both coding interviews and system design interviews:

Coding Interview Prep Resources:

Cracking the Coding Interview by Gayle Laakmann McDowell – A comprehensive book with 189 programming questions and detailed solutions. It’s often considered the coding interview bible, covering data structures, algorithms, and interview tips. Many candidates report this book significantly boosted their coding interview performance ("Cracking the Coding Interview" vs "System Design Interview – An Insider's Guide": Which is better?).
LeetCode (website) – An online judge with hundreds of interview-style coding problems. Great for daily practice; you can filter by topic and difficulty. LeetCode’s discuss section and solutions help you learn different approaches.
HackerRank or CodeSignal – Platforms offering coding challenges and contests. They help you get used to coding under time constraints and handling input/output, which is good practice for interview coding rounds.
Grokking the Coding Interview (DesignGurus.io) – An interactive course that teaches common problem-solving patterns for coding questions. Focusing on patterns can help in recognizing solutions faster for new problems. Check out Grokking the Coding Interview: Patterns for Coding Questions.
Interview Prep Books/Websites – Other popular books like Elements of Programming Interviews or websites like InterviewBit and TechInterviewHandbook offer structured problem lists and cheat-sheets for quick review of key concepts.

System Design Interview Prep Resources:

System Design Interview – An Insider’s Guide by Alex Xu – A beginner-friendly book with a collection of system design questions and step-by-step solutions. It covers how to approach each problem and is excellent for learning how to structure your thoughts. Many readers found that this guide “leveled up their understanding of system design concepts” and improved their confidence in tackling design problems.
System Design Primer (free GitHub repository by donnemartin) – An open-source resource that covers basics to advanced topics in system design, complete with real-world scenarios and even Anki flashcards for review. It’s very comprehensive (great for in-depth study if you have time).
Designing Data-Intensive Applications by Martin Kleppmann – A deep-dive book on the principles behind modern data systems (like storage, retrieval, scaling). It’s more advanced and theoretical, but reading select chapters can clarify why certain design decisions are made.
Tech Blogs & YouTube – Explore YouTube channels (e.g. Gaurav Sen, DesignGurus.io by Arslan Ahmad) provide free insights. They often break down popular system design interview questions and discuss trade-offs, which helps you learn how experienced engineers approach design problems.

Using resources wisely: Don’t just read or watch passively – actively engage. For coding, try to solve problems yourself before reading solutions. For system design, pause videos and think through your own design first. It’s also beneficial to use multiple resources to get different perspectives. For example, a combination of Cracking the Coding Interview for coding and System Design Insider’s Guide for design covers both bases. In fact, many candidates find that using both types of resources in tandem solidifies their skills – one resource solidifies coding skills, while the other preps for system design rounds.

Time Management Strategies for Dual Preparation

One of the biggest challenges in prepping for two interview types is managing your time. Here are some effective time management strategies to tackle both aspects without feeling overwhelmed:

Create a Schedule (and Stick to It): Plan out your week in advance. For example, allocate 1-2 hours on weekdays for coding practice and a longer block on the weekend for system design study or vice versa. Treat these like class or meeting times that you can’t miss. A written schedule or calendar reminders can keep you accountable.
Use Small Chunks of Time: You don’t always need multi-hour blocks. Use daily downtime to your advantage. If you have 30 minutes free, solve a quick coding problem or review a system design concept. Even short focused sessions (30-45 minutes) can be effective (How can I spend time preparing for coding interview while working as a full time software engineer?). Consistency beats cramming – even a bit of daily practice adds up over weeks.
Set Specific Goals for Each Session: Avoid aimlessly “studying.” Instead, decide what you’ll achieve in a given session. For example: “Tonight: implement 2 graph algorithms and analyze their complexity,” or “This Saturday: design the backend of a messaging app focusing on database schema and APIs.” Having a clear goal ensures you use time efficiently and get a sense of accomplishment.
Mix It Up to Stay Fresh: Doing the same type of prep for hours can reduce efficiency. Break your study time into segments – e.g., one hour coding, then take a break or switch to a system design article/video for 30 minutes. Alternating can keep your mind engaged and prevent fatigue, while also reinforcing both skill sets each day.
Track Your Progress: Keep a simple log of what you’ve done each day. Over a week you should see entries for both coding and system design tasks. If you notice you’ve gone several days with only coding practice, it’s a cue to include a system design session (and vice versa). Tracking helps maintain balance.
Prioritize Rest and Health: Managing time isn’t just about study hours; it’s also about rest. A fresh mind absorbs knowledge faster. Make sure to get enough sleep and short breaks during study sessions. Burning out will set you back. Schedule short breaks in long study sessions and take at least one day off fully each week to recharge.

By managing your time wisely and maintaining discipline, you can cover a lot of ground in both coding and system design prep. Remember, it’s a marathon, not a sprint – steady, regular progress beats last-minute cramming, especially when two distinct subjects are involved.

Common Mistakes to Avoid

When preparing for system design alongside coding interviews, beginners often stumble into some common pitfalls. Be mindful of these mistakes to ensure your prep is efficient and effective:

Focusing Only on One and Ignoring the Other: It’s a mistake to pour all your time into coding practice while postponing system design study until the last minute (or vice versa). Even if one type of interview is your strength, completely neglecting the other will leave you unprepared. Avoid tunnel vision – maintain at least some practice in both areas every week.
Not Understanding Fundamentals First: Jumping into solving complex algorithm puzzles or designing intricate systems without solid fundamentals can backfire. For coding, make sure you understand why algorithms work, not just memorizing solutions. For system design, ensure you grasp basics (like how the web works, database basics, etc.) before tackling a full system. Skipping fundamentals might save time early on, but it leads to confusion later.
Rote Memorization of Solutions: Memorizing a bunch of coding problems solutions or a few system design case studies is not true preparation. Interviewers can tell if you truly understand or if you’re regurgitating memorized answers. Instead of memorizing, focus on patterns and principles. Learn how to derive solutions step by step. This way, even if you get an unfamiliar question, you can handle it by applying those principles.
Lack of Hands-on Practice for System Design: It’s common to watch system design videos or read blogs and feel “I get it” without ever practicing it out loud. Avoid passive learning. You should practice explaining your system designs as if you are in an interview. This includes drawing diagrams (even rough sketches) and verbalizing your thought process. Without practice, you might freeze up when you have to do it in a live interview, even if you understand the material.
Overloading and Burnout: Trying to cram 8 hours of study every single day for both coding and system design is unsustainable. Some beginners make an ambitious schedule and then burn out, losing consistency. It’s a mistake to equate quantity of study with quality. It’s better to have shorter, consistent study periods than sporadic marathon sessions. Don’t forget to take breaks and keep a pace you can maintain over several weeks or months.
Neglecting Mock Interviews: Many candidates prepare thoroughly but never simulate the real interview environment. This is a mistake because coding on a whiteboard/in a shared doc or designing a system under interview pressure is a skill in itself. Failing to do mock interviews means you might be caught off guard by time management issues or communication difficulties during the actual interview. Avoid this by scheduling a few mock sessions for both coding and system design once you have the basics down.
Not Analyzing Mistakes: Simply practicing a lot isn’t enough if you don’t reflect on what you got wrong. A common error is to solve problems but not review the ones you failed or to design systems and not identify potential flaws in your design. Always loop back: review your coding solutions (and understand mistakes or suboptimal choices), and revisit your system designs to see what could be improved (maybe you forgot a requirement or a bottleneck). Learning from mistakes is one of the fastest ways to improve.

By being aware of these pitfalls, you can adjust your preparation strategy proactively. Avoiding these mistakes will save you time and help you progress more smoothly as you prep for both interview formats.

Conclusion

Balancing system design prep alongside coding interview prep might seem challenging at first, but with a structured plan and consistent effort, it’s absolutely achievable.

Remember that both skill sets complement each other – coding hones your problem-solving precision, while system design cultivates your big-picture thinking. By acknowledging the importance of each, allocating time for both, and using the right resources and strategies, you’ll become proficient in algorithms and capable of designing scalable systems.

In summary, start with strong fundamentals, practice regularly in both areas, use quality resources, and simulate real interviews. Stay disciplined with your schedule but flexible enough to adjust as you learn.

Avoid common prep mistakes by staying balanced and mindful in your approach.

With dedication and smart preparation, you’ll be well-prepared to tackle coding challenges and system design interviews confidently, paving the way to success in your tech career journey.