Crack LowLevel System Design Interviews (original) (raw)

Last Updated : 16 Apr, 2026

Cracking low-level system design interviews can be challenging, but the right approach makes it manageable. This article shares five key tips to help you break down problems, communicate clearly, and showcase your design skills effectively.

1. No Right or Wrong Answer For the Design Question

In industries getting a better design of the product is an iterative process and a lot of times refactoring of code also gets to happen to improve it. However, in the interviews, we only have limited time to come up with a design that should be good enough to convince the interviewer.

• Always start designing from the basic entity in your system and then iteratively proceed toward the higher components.
• That way chances of missing out on the basic components are less in comparison to that if you start with big entities in starting.

**Example: While designing a Parking Lot System, start with basic entities like Vehicle, ParkingSlot, and Ticket, then expand to higher-level components like ParkingManager.

2. Understand and Read the Question Properly

In interviews, even if you recognize a question, avoid rushing to write a memorized answer. First, understand the problem clearly, as requirements may differ from what you’ve studied. Stay calm, listen carefully to the interviewer, and proceed only after fully understanding the expectations.

• If you have read the answer prior to your interview it will definitely give you a head start, but don’t just sound as if you have mugged up the answer.
• Requirements in interviews may differ from what you’ve studied, so blindly repeating a memorized answer can create a negative impression. This can significantly reduce your chances of success.
• It's very important for you to understand the whole picture and then think before you jump to a conclusion.

**Example: If asked to design a Food Delivery System, confirm whether features like real-time tracking or payment integration are required before designing.

3.List the Requirements

Don't assume, just clarify with your interviewer about all the requirements and then write them down, this will help you to avoid confusion later and it will also help you proceed step by step. Once you have all the requirements clarified, they will become the base for design and you will be able to proceed step by step accordingly.

• Without clearly listing requirements, the design process becomes confusing as there is no clear direction to follow.
• Gathering and clarifying all requirements is essential, as they form the foundation for your system design.
• Once defined, use these requirements as a guide to design the system step by step in a structured manner.

**Example: For a Library System, list requirements like book search, issue/return, and user management before starting the design.

4. Think and Be Clear With Your Answer

After gathering requirements, take time to think and discuss your approach with the interviewer. Even if your initial idea isn’t perfect, collaboration helps you refine it with guidance. Engaging with the interviewer allows you to align your solution with expectations and make better use of hints provided.

• Interviews are time-limited (45–60 minutes), so trying to design everything first and then explain it is a mistake and often ineffective.
• Continuous discussion with the interviewer helps catch mistakes early, as they can guide you with hints and correct your direction.
• Also, it will save you a lot of time that you would be spending on correction and explanation later.

Always remember that your interviewer is there for hiring you and not for rejecting you, so feel free to seek help and hints if required, however, do not make it a habit at each and every step, as seeking too many hints and help can also be negative sometimes.

**Example: While designing a Chat Application, explain your idea for message flow and storage, and adjust based on interviewer feedback.

5. Practice, Practice, and Practice

Practice and consistency are essential for improving your skills, so regularly revise your notes and study materials before interviews. Even if you encounter a familiar question, use it as an advantage but avoid blindly repeating the same answer—adapt it thoughtfully based on the situation.

• Take a few questions and try to solve them and come up with the design on your own first and then if the solution is available somewhere just compare with that what is being missed or what can be done in a better way.
• Just do not go and directly read the solution, that way the learning curve will not be exponential. First, try and then go for a solution.

**Example: Try designing a Movie Ticket Booking System yourself before checking the optimal design to identify gaps.

Often people make the mistake of just reading the solution and going for the interviews, believe me, that’s not a very good habit, always try yourself first and then watch out for the available solution.