System Design Interview Questions

Gk K. - " can we use blomfilters to check existing usernames? and if both are creating at a time, like both are choosing some abcd , here system checks whether user with that name exists or not. so while checking , it will add an entry on redis (example) with this name as key and obtain lock using some distributed lock. , it will lock on that name. (like seat booking in bookmyshow) with some TTL value. so this check will happen once user enters his interest username and also while submit .. 2 times che"See full answer

Claudia S. - "What is a "cache controller"? With no more details it's difficult to tell what this question is about."See full answer

Adesegun K. - "While all branches should ideally be tested, some are more critical than others based on the following factors: A. High-Risk or Business-Critical Logic Branches that handle authentication & authorization (e.g., login, role-based access control) Financial transactions or payment processing logic (e.g., tax calculations, refunds, invoice generation) Security-related branches (e.g., encryption/decryption, token verification) B. Error Handling & Exception Paths Branches that deal with error conditi"See full answer

Satyajit G. - "It might not be a good idea to predict stock prices only based on reddit comments. You could create a signal from reddit comments that can indicate "social media interest" and feed it into a ML system (along with other features) that predicts prices. Collecting good data to train the model and evaluating it correctly are going to be huge challenges."See full answer

Tamil selvan R. - "May I know which tool is being used to draw flow diagram?"See full answer

Sourabh G. - "Functional Requirement Monitor health, metrics Alert in case of failure/anomaly Visualize the live health Analyse machines on periodic basis Non Functional Should not exert load on machines low latency Highly scalable Logs/Metrics Gathering push - machine gather and send to system and low priority background thread along with batching pull - heart beat check (for offline machines) Processing Real time streaming using Kafka/kinesis + Flink TimeSeries database for stor"See full answer

Abdurhman M. - "Start your stream Use the Post tab to: Choose where to post your live broadcast. Write a description. Select a camera, mic and screen (if screen sharing). Add a title for your live broadcast (optional). Select the primary language of the stream. ... Once everything is set, select Go Live."See full answer

Adrian V. - "What about sharding by Real Estate companies that are listing the homes? Because the homes can span zip codes. Then further shard by zip codes?"See full answer

Anonymous Stork - "You are working on a SaaS product that currently uses Basic Authentication (username/password) for API and application access. The security and compliance teams have mandated moving to a more secure, modern authentication mechanism — OIDC (OpenID Connect). Design the authentication system migration from Basic Authentication to OIDC. Discuss the architecture changes, the migration approach, and the rollout strategy. What are the technical challenges, impacts on customers, backward compatibility"See full answer

M N. - "Lyft mission. What do we mean by engagement here? We want higher rides , not just time spent on app. What does social mean? When we create interactions between riders. Lyft line is social. Ideas: Idea: Can we maintain interactions between riders by letting them ride with same people again? Benefit: Increases repeat rides. Idea: Giving riders an option to request a driver they rode with. Benefits: Increases social interaction between riders and drivers. Increases retention and # rides as"See full answer

Anonymous Hummingbird - "Assumptions: This is an entirely new app and not part of FB Clarification questions: Q: What type of doctors are they looking for? It seems like an app would be for a more generalist doctor to establish relationship and not some type of emergency situation A: Yes Q: When we say looking for doctors whats the scope of this? Should we include making the actual appointment, does this happen on platform? A: Yes, initial appointment Ok thanks based on that I think we have enough to get started. "See full answer