Meta (Facebook) System Design Interview Questions

Adam L. - "Discussed: Requirements of the system: latency language modality (assume keyboard typing) availability of data (assume cold start) success metric (accuracy of next word predicted?, or minimize false positives? -> accuracy to start) Data collection and processing: design ethical user experiments to collect typed out data design a simple tokenization strategy (word level encoding, character level encoding, byte-pair encodings, and discuss tradeoffs) collect data, and split"See full answer

Ajay P. - "Designing an evaluation framework for ads ranking is crucial for optimizing the effectiveness and relevance of ads displayed to users. Here's a comprehensive framework that you can use: Define Objectives and Key Performance Indicators (KPIs):** \\Click-Through Rate (CTR):\\ The ratio of clicks to impressions, indicating the effectiveness of an ad in attracting user attention. \\Conversion Rate:\\ The ratio of conversions (e.g., sign-ups, purchases) to clicks, measuring how well"See full answer

Vijay M. - "Very well done."See full answer

Anonymous Hummingbird - "Clarifying questions: · Is there a specific scenario we are building before? Example: urgent need for a specific type of blood vs building up blood banks proactively. You decide · This would be for mobile/web and integrate into the existing facebook product? Yes Ok before we get started I wanted to discuss the facebook mission: to give people the power to build community and bring the world closer together. I can see how blood donation fits directly into this, enabling blood donation helps"See full answer

BriskD - "I watched a couple of videos like this, one of them by Exponent staff (I think). It was disappointing that the architecture diagram and the walkthrough was a general layered architecture that you can apply to any backend system. I was wondering if there are videos that can be considered a reference material to watch, learn and improve on the tech (sys design) skills, and not so much about the soft skills."See full answer

Kartikeya N. - "C : Okay. So I would want to start with knowing what is the product for which we have to build a recommendation system. I : This is a photo sharing product. C : Okay. So is this something on the lines of Instagram? I : Yes C : Okay. And are we a new product co or we have some current product built already? I : You can assume yourself. C : Okay. Is there any demography or country we are targeting? I : No, this is a global product C : Okay. So, the biggest goal of any product recommendation system"See full answer

A B. - "Great explanation on each of the components and their use. During the interview would a PM candidate be expected to go in-depth for capacity estimation (e.g. storage estimation, bandwidth estimation etc.?)"See full answer

Usman B. - "System Components Data Collection Layer Posts with hashtags are asynchronously sent to Kafka topics Each message contains: hashtag, timestamp, userid, postid Multiple Kafka partitions ensure scalability and fault tolerance Processing Layer Apache Flink processes streams in real-time Implements sliding window aggregation (1hr, 24hr, 7d windows) Calculates topic popularity using weighted metrics: Post count User engagement (likes, comments) Unique user"See full answer

Scott S. - "Designing a Price Drop Tracker system like CamelCamelCamel involves creating a platform that tracks price changes for products on various e-commerce websites and notifies users when prices drop. Here’s a detailed system design for such a service: Functional Requirements User Registration and Authentication\: Users can register and log in. Support for social media logins (e.g., Google, Facebook). Product Tracking\: Users can add products to their watchlist for"See full answer

dreamingincode - "In the API design, the interviewer is switching between RPC style (operation based endpoints) and REST style (resource oriented). Sticking to one convention and explaining why it is preferred over the other e.g. REST if the twitter domain maps nicely to resources e.g. /tweet or /follower or /user would help to create a more consistent and unified API. It would make it easier for clients to integrate with the API as well."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

Rjj - "https://youtu.be/pHu6N3DTnCY?si=BkkVXZVUVRoE5cnt -> This is one video that I recorded for this question. Please go through and feel free to discuss further here or in the youtube comments"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

El hassane B. - "Why this seems like a cyber-security question?"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

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

Krishnan S. - "Excellent job Roshan, really liked the explanation. Which software were you using to explain the system design diagrams?"See full answer