Preparing for System Design Interviews
How to prepare for system design interview for FAANG companies for senior engineers?
Landing a senior engineer role at a FAANG company is a coveted goal for many in the tech industry. But, the system design interview can be a daunting hurdle to overcome. In this article, we'll go over some of the common aspirations, challenges, and tips to help you ace your next system design interview.
First, let's talk about some of the common aspirations people have when preparing for a system design interview. People want to:
To demonstrate expertise in software design, architecture and scalability
To impress the interviewer with technical knowledge and communication skills
To showcase real-world experience in designing and delivering complex systems
To secure an offer from a top technology company like FAANG
To increase salary and improve career opportunities.
However, there are some challenges that can prevent people from reaching their goals, such as:
Lack of hands-on experience in designing large-scale systems
Insufficient knowledge of current technologies, tools, and design patterns
Difficulty in articulating design choices, trade-offs and decisions
Pressure to perform well in a short amount of time in an interview setting
Competition from other experienced and qualified candidates
Inability to articulate past experience in a relevant and concise manner.
Don't worry, though! There are some tips that can help you overcome these challenges and improve your chances of landing the job. Here are a few:
Practice making design decisions on paper or with peers before the interview: For example, participate in design exercises and mock interviews with peers or colleagues to get feedback on your thought process and communication skills.
Study the latest technologies and design patterns: For example, regularly read technical blogs, books, and papers to deepen your knowledge of software design, architecture, and scalability.
Be prepared to explain your thought process, trade-offs, and assumptions: For example, in an interview, you can use diagrams and pseudocode to help explain your design and be ready to answer questions on why you chose a specific approach.
Rehearse frequently and make sure you can explain your solution in 5-10 minutes: For example, time yourself while practicing explaining your design to ensure you are concise and can effectively communicate your solution within the allotted time.
Be flexible and willing to modify your design based on feedback from the interviewer: For example, if the interviewer provides feedback or questions that challenge your design, be open to modifying it based on their suggestions.
Highlight your relevant experience and how it relates to the problem you are solving: For example, if you have designed and deployed a large-scale system in the past, be sure to mention it and explain how the experience will help you tackle the design problem being presented in the interview.
By using these tips, the candidate's interview performance is likely to be improved in several ways:
Increased Confidence: By practicing and studying beforehand, the candidate will feel more confident in their abilities and knowledge during the interview.
Improved Communication Skills: Rehearsing frequently and being prepared to explain their thought process and trade-offs will help the candidate communicate their design decisions in a clear and concise manner, improving their overall interview performance.
Deepened Understanding: By studying the latest technologies and design patterns, the candidate will have a deeper understanding of software design and be able to make informed decisions during the interview.
Flexibility and Adaptability: Being open to modifying their design based on feedback from the interviewer shows the candidate's ability to adapt to new information and changing requirements, making them a more attractive candidate to the company.
Relevant Experience Highlighted: By highlighting relevant experience, the candidate can demonstrate how their previous experience can be applied to the design problem being presented in the interview, making them a stronger candidate for the role.
Here are top 10 questions that you may prepare for a system design interview:
How would you design a scalable web service that can handle millions of requests per day?
How would you design a distributed cache to store frequently accessed data?
How would you design a social network platform like Facebook or Twitter?
How would you design a recommendation system for online shopping or streaming services?
How would you design a distributed file system that can handle large amounts of data and multiple read/write requests?
How would you design a real-time bidding system for online advertising?
How would you design an event-driven architecture for a real-time messaging system?
How would you design a highly available and fault-tolerant system for payment processing?
How would you design a logging and monitoring system for tracking application and system metrics?
How would you design a search engine to index billions of web pages and handle multiple search queries per second?
It's important to note that these questions aren't meant to trip you up, but rather to assess your problem solving skills, technical knowledge, and communication skills. So, don't be intimidated! Just focus on answering the questions in a clear, concise, and relatable manner.
Here's a general approach to answering these types of questions:
Start by understanding the requirements and constraints of the problem. Ask clarifying questions to make sure you understand what is being asked.
Break down the problem into smaller subproblems, and think about how you can solve each subproblem independently.
Consider trade-offs and make decisions based on the requirements and constraints.
Present your solution, including any trade-offs or assumptions you have made, and explain your thought process. Be prepared to answer questions and defend your solution.
Be open to feedback and be willing to modify your solution if necessary.
For example, if you are asked to design a scalable web service that can handle millions of requests per day, you may start by understanding the requirements, such as the expected number of requests, the types of requests, the response time requirements, and the budget constraints. Then, you may consider the following steps:
Divide the problem into smaller subproblems, such as load balancing, data storage, and caching.
Choose a load balancing algorithm to distribute requests across multiple servers.
Decide on a data storage solution that can handle large amounts of data, such as a NoSQL database or a distributed database system.
Implement caching to store frequently accessed data, such as using a distributed cache like Redis.
Consider using techniques like auto-scaling to dynamically adjust the number of servers based on the load.
Let's take another example. If you are asked to design a recommendation system for online shopping or streaming services, you may start by understanding the requirements, such as the types of items being recommended, the number of items to recommend, and the criteria for recommending items (e.g. user preferences, popularity, etc.). Then, you may consider the following steps:
Collect data about user preferences, such as the items they have purchased or viewed.
Use an algorithm such as collaborative filtering or matrix factorization to generate recommendations based on user preferences and similarities.
Store the recommendations in a cache or a database for quick retrieval.
Consider using techniques such as A/B testing to continually improve the recommendation system.
Take privacy and security into consideration when storing and using user data.
Let's take another example. If you are asked to design a highly available and fault-tolerant system for payment processing, you may start by understanding the requirements, such as the expected volume of transactions, the response time requirements, and the acceptable downtime. Then, you may consider the following steps:
Use a load balancer to distribute transactions across multiple servers to ensure high availability.
Store the transactions in a database system that provides automatic failover, such as a distributed database like Cassandra or a cluster of databases like MySQL.
Consider implementing a backup system to ensure that transactions can be recovered in the event of a failure.
Use monitoring tools to detect and respond to any failures or performance degradation.
Consider implementing multiple layers of redundancy, such as multiple data centers, to minimize downtime.
Let's take one more example. If you are asked to design a real-time chat system for a social networking website, you may start by understanding the requirements, such as the number of users, the expected message volume, and the response time requirements. Then, you may consider the following steps:
Decide on a message queueing system, such as RabbitMQ or Apache Kafka, to handle the real-time delivery of messages.
Store the messages in a database system that provides fast retrieval, such as a NoSQL database like MongoDB or a key-value store like Redis.
Use WebSockets or a similar technology to enable real-time communication between the client and the server.
Implement security features, such as encryption and authentication, to protect sensitive user data.
Consider using techniques such as auto-scaling to dynamically adjust the number of servers based on the load.
For all of these examples, it's important to keep in mind the following tips to enhance your interview performance:
Communicate your thought process: Explain your thought process, trade-offs, and decisions as you work through the problem.
Be flexible: Be prepared to change your approach based on new information or feedback from the interviewer.
Be concise: Focus on the most important parts of your solution and avoid getting bogged down in details.
Be aware of trade-offs: Be prepared to explain the trade-offs of your solution, such as the trade-off between scalability and complexity.
Practice: Prepare for the interview by practicing solving system design problems with friends or in mock interview settings.
By keeping these tips in mind, you will be able to demonstrate your technical skills and ability to work through complex problems in a clear, concise, and effective manner.
It's also important to be knowledgeable about the company's specific needs and requirements, as well as any relevant technologies or tools. For example, if you're interviewing for a company that heavily relies on a particular technology, such as Amazon Web Services, you should be familiar with that technology and its capabilities. Additionally, you should have a good understanding of various design patterns and be able to explain how they could be applied to solve specific problems.
Finally, it's important to be a good communicator and be able to articulate complex technical concepts in a way that is easy for others to understand. This is especially important in a system design interview, where you'll need to collaborate with the interviewer to design a solution that meets the requirements. By being a good communicator and demonstrating your technical knowledge, you'll be able to impress the interviewer and stand out from other candidates.
In conclusion, by preparing thoroughly, practicing your problem-solving skills, and being a good communicator, you will be well on your way to landing a senior engineering role at a FAANG company. Good luck!