System Design Interview Questions

Kshitij A. - "The question is bit vague (I guess deliberately) so I believe firstly we shall ask questions and resolve ambiguity. Some initial questions could be : 1) Is this one time activity or something that should be done on continuous basis. If continuous basis then at what frequency. 2) How much staleness is acceptable in SYSTEM Y data 3) Are there any limitation in SYSTEM Y and is it fair to assume that we would need some kind of transformation to bring data into SYSTEM Y schema. 4) What kind of vol"See full answer

Harshit G. - "Great. I will start by understanding the goal of Google Photos and how it aligns with the goal and mission of Google. After defining goals, I will talk about the user actions which will contribute towards this goal. Based on these actions, we will define metrics. Check-in with the interviewer on the approach here. Assuming that this looks good for the interviewer to proceed. Google Photo - Helping users organise & manage their pictures. Completely in line with Google's mission. Thinking ab"See full answer

Eshan P. - "Background A. Objective Lyft has a presence in Toledo, Ohio. At our current revenue per ride of $6, we can match 60% consumers requesting a ride with a driver. Our goal is to maximize net revenues in the next 12 months by figuring out the optimal revenue per ride. B. TLDR Summary · With a target market of (~100K-138K) consumers, on a $25 charge to consumers, Lyft should pay $20.75 to drivers and fix its share at $4.25 to maximize its net revenues over a 12-mont"See full answer

David S. - "I am about to interview at Google and it seems like they are requiring to use Google Drawings"See full answer

Sai vuppalapati M. - "At a high level, the core challenge here revolves around building an effective recommendation algorithm for news. News is an inherently diverse category, spanning various topics and catering to a wide array of user types and personas, such as adults, business professionals, general readers, or specific cohorts with unique interests. Consequently, developing a single, one-size-fits-all recommendation algorithm is not feasible. To enhance the personalization of the news recommendation algorithm,"See full answer

Eduardo C. - "I started asking some questions regarding the constrains of the system: An antena is emitting a signal that says if the tagged device was out of the room where the interview was happening. I was able to decide which would be the schema for the Antena's message. The antena is sending the info of multiple users. The system doesn't need to push notification to the users when the user left the device behind. Upon reflection, this is what I recollected doing. I propuse the json schema a"See full answer

Shivastuti K. - "For somebody who needs accessibility accommodation, this doesn't have a transcript so it is not useful to me."See full answer

Faraz A. - "Scoped out problem constraints - how much data to download, how many computers, and how much time, how you can be detected (decentralized load). Designed a web crawler."See full answer

Anup S. - "Inventory Service and Registration service can they be in SYNC always ?? The "experience layer" needs accessed by Hotel owners also ??? How does real time inventory come from all Hotels ???"See full answer

Kamal .. - "Designing a video streaming system like Netflix or Facebook Video involves addressing multiple aspects, such as scalability, availability, low latency, and high performance. Here's a high-level design: System Requirements Functional Requirements: User Management: User sign-up, login, and profile management. Subscription plans and payment integration (for Netflix-like systems). Content Management: Upload, edit, and delete videos. Categorize content (genres, recommendations). Video Playback: S"See full answer

Nitika B. - "Equation: Cost = Amount of storage required per year * Cost per year * 3 Amount of storage required per year = DAU * Storage requirement/user * 365 Assumptions: Cost per year = $99 = $100 Smart phone growth rate = 2% (But negligible at Pixel level) Annual Smart phone users = 2.8B Android users = 76% Google Pixel users = 1% Total Users = 2.8B * 0.01 = 280M *0.01 = 2.8M Method 1: Cost = Active Users + Cost/year * Number of years Cost = 3* 2.8M * $100 = 8.4M*100 = $840M Cost = $8.4B Method 2: C"See full answer

Aymen D. - "It would have been more interesting to focus on the system design rather than the Trie DS, Interviewee could have just mentioned the Trie and passed to things more important. Interviewee should have focused on the factors on which he wants to scale the API servers, popularity of the query parts ? region may be ? A hash of many factors ? Caches should have definitely be discussed, Cache eviction policies, Cache invalidation managements... Interviewee should have mentioned which kind of API pro"See full answer

San S. - "How might the system design change if it is limited specifically to a web/mobile use case?"See full answer

gdecuri - "Load Balancer, Multiple API Servers, game Service, pub-sub system, HTTP Long Polling for status updates, write-through cache. No SQL DB to store user, game, and move information."See full answer

Ushita S. - "The back-of-the-envelope calculation is very well done!"See full answer

Linying W. - "Very helpful! But I have a question: the location of drivers can be changing every minute, so won't reading from location cache returning stale data?"See full answer