10 Proven Steps to Ace System Design Interviews with Confidence

What is the purpose of a system design interview?

System design interviews test a candidate’s ability to think through the system and design large-scale systems. It involves designing system architecture and high-level design (low-level design is skipped in this phase). It also tests one decision’s making ability since one has to make trade-offs among multiple design choices.

It also reveals a candidate’s analytical and rational thinking. Apart from this, a candidate’s communication skills and thinking process are also revealed for assessment. Clearly, cracking system design interviews needs a systematic approach.

Here are 10 steps to crack this interview:-

1. Understand the problem(functional requirements): The first step in any system design interview is to understand the problem. Make sure you clarify the requirements, constraints, and use cases. This will solidify your understanding of the required aspects of the system that is being asked.
2. Clarify scalability and performance requirement(non-functional requirements): Scalability and performance are main concerns in system design interviews. Make sure you consider these factors as you design your system, and be prepared to discuss trade-offs between performance, scalability, and availability.
3. Fix your approach: Discuss your approach with the interviewer and choose one with his/her guidance. It is important to convince your approach to the interviewer. He/She will help you by highlighting loopholes in your approach.
4. Design main architecture first: This will be the topmost design diagram. It should be simple and clear. it should show data flow from external world to system.
5. Think in terms of Components and modules:- Once the topmost design is ready then you can focus on individual components. If the interviewer asks for details any component only then provide it.
6. Express Your Thoughts: Be vocal while you are designing a system. It helps the interviewer to understand your thinking process and communication skills.
7. Be flexible to change design: If your design does not fulfill non-functional requirements (or some parts of the design is not convincing) then be open to suggestions from the interviewer and change the design.
8. Use examples and visuals: Using concrete examples and visual aids will add value and can be helpful in communicating your ideas to the interviewer. Use diagrams, flowcharts, and other visual aids to help illustrate your design.
9. Discuss trade-offs: System design is all about making trade-offs between different factors, such as performance, scalability, maintainability, consistency, fault-tolerance and cost. Main focus here should be the trade-off that you made and why?(Convince interviewer on this).
10. Conclusion:- Always conclude your design. It basically summarise your system design round and provides blueprint of your solution to the interviewer.

Conclusion

In conclusion, excelling in a system design interview involves a systematic and communicative approach. Begin by comprehensively understanding the problem, ensuring clarity on functional requirements, constraints, and use cases. Transition to addressing non-functional requirements, emphasizing scalability and performance while being mindful of trade-offs.

Engage in a collaborative discussion with the interviewer, seeking guidance and refining your approach based on feedback. Design the main architecture with simplicity and clarity, visualizing data flow from the external world into the system. Delve into component-level design when prompted, expressing your thoughts vocally to showcase both your thinking process and communication skills.

Be open to adapting your design based on the interviewer’s insights, and use concrete examples and visual aids to enhance clarity. Lastly, conclude your design, summarizing key aspects and providing a blueprint of your solution. This holistic approach not only showcases technical prowess but also effective problem-solving and communication abilities in a system design interview scenario.

If you follow above steps with lots of practice then you will ace through the system design round with flying colors.