Learn System Design
In a Hurry
Core Concepts
Key Technologies
Patterns
Advanced Topics
Question Breakdowns
Vote for what we break down next
What questions or deep dives would you like to see next?
Propose a New Question
Please look through the list to make sure your question isn't already there.1995
Payment System
A payment system similar to Stripe or PayPal.
1135
Design distributed rate limiter
- Design a horizontally scalable distributed rate limiting solution to prevent facebook's public api abuse
949
Design a Flash Sale Site
Limited number of items for sale with millions of active buyers fighting for remaining items
626
Design "likes" counter
Design a system that tracks the number of “likes” (posts / tweets / photos) at scale.
619
Design a recommendation system for netflix/prime/Hulu to recommend movie
Design a recommendation system for netflix/prime/Hulu to recommend movies or TV shows
572
Design the auto-complete/type-ahead backend
Design the backend for an auto-complete system, like Meta, Google or Amazon.
522
Design Metrics Monitoring and Alerting System
484
Design Facebook post privacy functionality
Users have the ability to choose the privacy of their posts (Only me, Friends, Public). If possible, also get into Friends of friends and custom lists.
472
Design CamelCamelCamel
price tracking system
368
Design Google Calendar
Design a calendar service that people can create events, invite others and suggest meeting rooms
304
Design meta chess
- Design meta chess. Store all the games and events and player moves. How do you design "undo" if each player can undo their last (or their two last) move(s)? Compute and maintain the scoreboard of billions of players? Top 100 games and winners.
291
Design distributed message queue
Functional Requirements - Client should be able to create a queue - Producer should be able to send message - Consumers should be able to receive messages - Consumer should be able to delete a message - delete queue.
246
Design a leaderboard
User's have a list of friends and can see their leaderboard ranking among their friends and among global users. System should scale to millions of users per day.
229
Create Key/Value Store
222
Design a notification service
Notification to other services or notification to users
221
Design Spotify
214
Design ChatGPT
208
Design a blob store like s3
201
Design payment system
Lime Venmo, PayPal
194
Deep Drives Apach Flink
Five deep drives of Apach FLink and how to use it, why to use it and compare it with the other tool
191
Distributed Logging and analysis
Petabytes of data per second ingestion, petabytes of data per second while querying.
186
Recoomendation system in Netflix
150
Design Google Maps
138
Design an E-Commerce System
Design an E-Commerce system with a functionality to handle billion $ sale days.
129
Design CDN
we have to build content delivery network
124
Design Booking.com
Hotel booking app like Booking.com, Agoda etc
103
Design ZooKeeper
92
Design a Parking Lot
89
Design a Rate Limiter
88
Deep Dive - ETCD/Zookeeper
85
Deep DIves: Apache Flink
84
Design GoogleMeet
Online realtime video conferencing tool
74
Design digital wallet
Users can check the wallet balance, add/view transactions and support transfer between accounts.
70
Design web crawler
Meta twists this question a bit and asks peer to peer approach assuming we have 10,000 phones or machines and use those to crawl the web. No system design course has clearly demonstrated this so far, so I am really interested to see your take Evan.
69
Design Stock Exchange
A lot of system design for stock exchanges out there focus on distributed systems rather than the requirement of low latency order matching which should be done in memory rather than utilizing queues and what not. Would love your perspective
68
Transactions deep dive
Can you please explain how transactions work internally. For example how rollback will work in a simple in-memory key value store. Also it will be great if you can touch upon the distributed transactions. Thanks.
64
Design YouTube
64
Deep Dives - Kubernetes
61
Design meta chess
- Design meta chess. Store all the games and events and player moves. How do you design "undo" if each player can undo their last (or their two last) move(s)? Compute and maintain the scoreboard of billions of players? Top 100 games and winners.
59
Design amazon product/inventory management
59
Tagging System
multiple services would like to store tags Cofluence for page, Jira for tickets and etc with CRUD and things like all pages per tag, dashboards and etc.
58
Design Status Search
Context: Every user can post something as "status", at any given time, one user can only have one status (vs multiple posts). Build a search system which should enable users to search the statuses.
57
Design Live Streaming System
Like Hotstar, Youtube or Netflix where millions of users are watching concurrently. How to minimize the live feed latency and scale for sudden spike and drop in traffic. System should be able to handle 50M-100M concurrent users at a time.
57
Design Zoom
wonder how this differs from designing whats app
55
Design Google News
Any news aggregator service
55
Design Live Video Streaming System
Designing a Live Video Streaming System Like ESPN
53
Design a Single Server Memcached
Might also extend that to cluster level memcached as well.
53
Design Twitter
50
Design Shopify
Design Shopify, an e-commerce platform where users can easily create and manage isolated web stores with customizable templates, APIs, plugins, and automated hosting. Ensure scalability, security, and efficient monitoring and maintenance.
50
Deep Dive: TimeSeries Database
49
Design weather app
48
Deep Dive - Spark
46
Design a food delivery app
A food delivery app like doordash or swiggy or zomato
46
Design I18N and L10N system
- Build system that helps developers to add new strings in application - Also allow auditing of those string - string should handle pronouns, numbers, format, unit conversion etc.... - manual verification vs ML verification - enable translators
46
Deep dive - Zookeeper
45
Design Slack
45
Deep Dive MapReduce
MapReduce, Hadoop, HBase, Hive..
37
Design a billing system
35
Job scheduler
- scheduling job - dag scheduling
33
Google photos
33
Design Splunk - Logging and Metrics Monitoring System
32
Design a banking app
29
Design Proximity Service like Yelp
29
Design Machine Learning Platform
29
Deepdive MongoDB
28
Distribute 6M burgers in 10 minutes.
No one should get more than 1 burger. We should distribute exactly 6M burgers.
25
Mock interview to get requirements
This is not an interview question specifically, but with both Evan and Stefan, I think it could be helpful to watch how an interviewee susses out requirements in a mock scenario without having practiced or knowing the problem.
24
Design a Feature Flag System
- Millions of users - Target individual users and % of users - Admin UI - Backend only
24
Design url shorter system.
Design distributed url shorter systems like tinyurl, linkedin etc.
24
How to design a Ledger System for Payment Gateway
Asked in Stripe
23
Design Cab Sharing / Ride Sharing App
Multiple (3-4) user can share a cab, it can be either like Uber cab sharing or something like if I am driving from point a to b as a user I post that & anyone willing to travel on same route can pair with me and pay me for the part of ride, quickride
23
Design Amazon Lockers
1. User can select nearby lockers at checkout. 2. System should generate OTP until used by user to unlock locker.
23
Design Twitter/ X Trending hashtags
Find top k hastags based on location and category. User can also search for past trending hastags
23
Design a webhook
A webhook can be a POST http endpoint called by an authenticated third party client. The client will call the webhook with a url and a message payload. The webhook should lookup the URL in the internal database registry and send the message to it.
22
Distributed high scale telemetry system
Telemetry/Metrics system such as Datadog, Splunk etc
22
Design google calendar
Focusing on the notification system (users can be in different time zones, each reminder should be sent only once, set reminders with frequency/interval, i.e. once a week, twice a month, etc.)
22
Design a hotel booking system
21
Design FIFO Pubsub system
Design a Pubsub system that makes guarantee FIFO delivery. I was asked this question during my interview.
21
Design Tiktok
short video platform such as Tiktok, youtube shorts, etc.
21
Deep Dive - ZooKeeper
20
Design Online Judge
A online coding judge like Leetcode which hosts coding contests, allows users to test and submit code, tallies scores and maintains a leaderboard
20
Design Amazon
E-Commerce checkout!
20
Flights Aggregator - Skyscanner
19
Design subscription system
Got asked at Google
19
Design a Notification Delivery System.
Something like One signal.
19
Recommendation Systems
Video recommendation, Product recommendation etc..
19
Deep Dive on API design: RestAPI and GraphQL
17
Design Advertising Platform for Ad Reporting
1. Analytical Load Serving 2. Data Skewness handling 3. Realtime Reporting
17
Designing a key value store like Redis
16
Design chess game between human and ai
- Determine how points are assigned for every move and how to determine winner/looser/draw state
16
Design WhatsApp
16
Design Robinhood
- Live stock price updates per second of 7000 tickers - Getting historical data of a stock for a timeframe for displaying the chart. The stock exchange in this case gives all the data points for a stock. For 1 month, all the data points each second
15
Design YouTube
15
Design Gmail/Outlook
send and receive an email including attachments, filter and search through emails, and add tags to label emails
15
Design Code Deployment
Global and fast code deployment system.The system take the code. Builds the code into a binary and deploys the code globally in an efficient way. scale and deploy code to application servers all around the world. Addition NF requirements
14
Design a time series db
14
design jenkins
Design CI/CD system such as jenkins.
14
design Chat GPT
14
Deep Dive - Raft v/s Paxos
14
Design a multiplayer game matchmaking system
User's should be able to join matches of 12 players. Matching should be as fast as possible while keeping players close together. Players should be matched on their skill level (Win:Loss ratio etc). Should support ~1M players concurrently.
14
Design a typeahead feature
14
Online Bank
Design online banking system
14
Design an authentication service
An IdP like Okta that can perform federation and access to cloud-based apps.
13
Design Google Calendar
google calendar - unique link generation, emphasis on how to store a meeting invite with multiple participants - which is recurring, reads (across globe) and writes - create, update, delete are efficient
13
Design a hotel reservation system
Hotel reservation system question has some nuances. It can be as simple as a single hotel reservation to all the way up to a hotel chain reservation. This is different from Booking.com, as that site doesn't handle the actual reservation itself.
13
Design Mint like platform
A personal financial management platform for comprehensive view of finances in secure way.
13
Design a bidding system
Where users can bid
13
LLD Interview Guides
Please make some sort of LLD interview guide.. 1) Can be like the hurry section for system design 2) Or specific problems
12
Design Peer to Peer Payment System
Like Venmo/Cash app allowing people to send money to other people.
12
deep dive into flink
12
Deep Dive Cockroach DB
12
Deep Dive - S3
A deep dive into a Blob store like S3 would be great. Pre-signed URLs, CDN via Cloudfront, ACLs, cold storage etc.
11
Design a rate limiter
11
HTTP downloader
11
PSP like VISA
Design a payment service provider like VISA.
11
Design google calendar
Focusing on the notification system (users can set reminders with frequency/interval, i.e. once a week, twice a month, etc.)
11
Design credit card system
System to process millions of transactions, always validating the customer's limit in every transaction
11
Design a Distributed Job Scheduler for Millions of Tasks in Daily Operation
11
Design Github/Gitlab
11
recommender system
Machine learning approach for folks interested in ML system design.
10
Design Steam
Game creators, can create new games, publish and upload files. Users can search for games, add to cart, buy and download.
10
Design an in-memory db
10
Blocking IPs from a specific country
We can't serve data to banned IP addresses. This country exposes a web interface - http://security.gov.x/ - that just tells us for any given IP address if it’s banned or not. you have to solve it within two months so no need hot fix but no redesign.
10
Design a reminder service
Users can schedule a onetime or recurring reminder which will send an email / push notification to the user. The reminder should be delivered exactly once within 5 minutes of the time. It should scale to millions of users.
10
Design a payroll system
For HR type software
10
Deep Dive - ElasticSearch
10
Design Paypal
10
Deep Dives - Zookeeper
10
Deep Dive - Zookeeper
10
Design Batch Processing System
10
Design a heat map
Create a system where every driver is sending their location in real time, plot a heatmap showing the number of drivers in particular location in last 20 minutes, consider 1 minute bucket.
9
Explore Distributed Concurrency Control
Go deeper into concurrency control between multiple instances of a microservice. For example, in the Ticket Master exercise, explore how we could control the concurrency when multiple instances of the Booking microservice tries reservice same ticket
9
SQL vs NoSQL
During the design which DB is best suited for the particular requirement and why ? Pros/Cons of it
9
Design Recommendation System
Something like Amazon's "Customers who bought this, also bought these N items"
9
Deep Dive: GraphQL
9
gossip protocol deepdive
9
Discuss Queues
Apart from Kafka, it would be good to have deep dives on Rabbit MQ/Redis Pub/Sub, Amazon SQS etc
8
Design whatsapp/messenger
8
We could use a dark mode on this site
8
Design a money transfer application
8
Design a distributed counter
8
Design Version Control system
Design a system like github
8
Design Distributed Logging/Tracing
A system like jaeger
8
Design what database to choose
This is more kind of an overview. Can you guys make a video on what database needs to be chosen for different type of use cases.
8
Design Snapchat
8
Create a digital wallet
8
Gmail
8
Designing a Music Recognition System like Shazam
system should be able to identify a song by listening to a short audio clip provided by the user. Once identified, the system should return details about the song, including the title, artist, album, and a link to listen to the full track.
8
Design Block Storage System .
I was asked this question within Amazon . The question is "Design a block storage system that can reduce the fragmentation of the disk and provide durable storage devices on demand" . Something like AWS Elastic Block Storage.
8
Design IAM system
8
Design Instagram Live
8
Deep Dive: Consensus Algorithms
Look into raft, paxos, multi-paxos, etc . Bonus if things like distributed transactions can be covered along with it.
8
Design a donation app
Should be a limited event for donation. Participants should be able to donate to different companies. Show donation received so far. You can add constraints as needed.
7
Planet Scale Metrics Ingestion Platform
Backend infrastructure for a metrics platform that scales for several zones/regions across the globe for ingestion and support queries for alerts, and on-demand incident response
7
Tagging service system design
https://leetcode.com/discuss/interview-question/system-design/838025/Design-a-tagging-system-like-tags-used-in-stack-overflow
7
Design a Fitness app
Tracks biometrics based on geolocation and activity
7
short url system design
system design for generating short urls and routing the short urls
7
Design a proximity Service
7
Design multiplayer chess with leaderboard
Multiplayer chess system design - similar to chess.com, competition, leaderboard, etc.
7
Design a distributed load balancer
Distributed load balancer optimising for different work loads
7
Design LinkedIn
7
Design a Telemetry Sysytem
Like Prometheus. Connect with external apps, record metrics, failures, events and logging.
7
Design Webhook
7
Design notification system
How would you 90M followers of a celebrity that they are going live
7
Design Reddit
Forum for discussion
7
Centralized System for Authorization
Design a central Authorization system that's capable of handling any combination of user(s)/entity/column level restriction centrally (similar to Google’s Zanzibar)
7
Design Facebook i18n
7
Design ESPN Fantasy Sports
App that allows users to create and join fantasy sports leagues for a variety of sports. Design Gaming app to handle millions of concurrent users, providing real-time updates, league management, and live scoring
7
Deep Dive - Mongo DB
7
Design Airbnb
7
Design Coinbase
Design a centralised exchange for buying, selling and transferring crypto
6
Design video sharing website (twitch) copyright video detection
Design a service similar to twitch that flags and deletes copyrighted audio in videos if another user has uploaded it (copyright infringement)
6
Design a distributed lock with TTL
6
Design Robinhood
Robinhood - how it gives real time stock data and handles market crashes
6
Sports Live Streaming
Streaming sports matches to millions of users in real time.
6
Design Weather App
Design a weather app that would retrieve data from NWS in hourly fashion When a user requests for weather data, he should get the most recent one. <10 stale data is acceptable
6
Deign Google Photos
6
Deep Dive - Neo4J / Graph Database
6
Google Maps
6
Design Reels
6
Design a Rate Limiter
Design rate limiter puts a limit on the number of requests coming from a client/device to a service and throttles requests that cross the predefined limit.
6
Design Stock Exchange
Instead of Broker App, design a Stock Exchange including Matching methodology.
6
Design an eCommerce system like Amazon
6
Design FB Internationalisation System
You have an app and you want to design an i18n system for them. When the user changes languages, all the strings have to change to that specific language.
6
localization system
-Design a system that provides a localization feature for Facebook - the user creates a post in a language and has the option to translate that to other languages of his choice.
6
Design fraud detection service
5
Online Donation/Charity System
5
Design a price alert system
5
design YouTube
Youtube/ Netflix
5
Design Street View in Google Map
5
Secure System Design for existing problems
Would be great to have some examples on how to approach secure system design interviews. Most of these focus on the SWE perspective but would be helpful to refocus around security engineering interviews.
5
Design real-time livescore sport
Like SofaScore, where Users can watch what is happening real time in a particular match. Taking care of important matches like World Cup Final or Super Bowl with inputs flowing manually or automatic from stadiums
5
Design Venmo/Paypal
Fintech being on the rise, design a system like venmo or paypal that makes it easy for users to send/receive money to/from each other. Staff/Senior: After you've implemented the system, discuss the security implementation you would consider.
5
Design a HighFrequency Trading Platform
5
Design a Marketplace System
5
Design the Google Doc
5
Design Robinhood/Stock trading platform
System that can be more as an orchestrator between client and stock exchange for real-time prices. Also, execute trade with the lowest possible latency similar problem that hfts trying to solve to make the highest profit.
5
Design Food Deloivery App
Design food delivery app like UberEats, Doordash
5
Design ChatGPT
design LLm model using prompts. Emphasize on Scalability availability and how model should be trained
5
Design Tiktok
5
Design Instagram Story
5
Design e-wallet
5
Design a real-time fraud detection system
Design a system that extracts transactional data, apply complex transformations (e.g. anomaly detection, pattern matching), and load results into a monitoring or alerting system in near real-time.
5
Design a voting system
users can cast multiple votes, latest vote counts. High accuracy vs low latency(real time) design
5
Design a Logging System
Create an logging system with Application and Processing server
5
Deep Dive PostGIS (Postgres) & Geo Hashing (Redis) for Proximity Searches
Deep dive should cover quadtrees and base32 encoding used by PostGIS and redis.
5
Design alerting system
Design a system for the alerting which checks if the alert condition is being met. Scale can be across 1000s of services, each having 5 APIs, each API having 10 alerts (like reliability, failure counts, latency both percentiles and average) on avg.
5
Design a Machine Learning System to prevent sales of guns through ads
There are not many staff level solutions for MLSD out there.
5
Stock Price Alerts System
Design a system where a user can have X favorite stocks and has subscribed to their changes. Users will set some rules for price drop/ price rise above a threshold or % value and if the rule is satisfied then we have to send notification to the user
5
Design HTTP Resourcer/Downloader
5
Design AuthN & AuthZ system
5
Design CI/CD
5
Design Zookeeper
5
Design News Aggregator :
1. Fetch news Articles from multiple news publishers 2. Generate custom news feed for Users based on their interests and the publishers they follow
5
Real-Time Data Processing Pipeline
Design a system to process real-time user activity logs (e.g., clickstreams, app interactions) and provide analytics in near real-time
5
Design Venmo
Can we talk about event sourcing and how does it fit in to a money transfer system, like Venmo. Users can transfer money between each other, and a delay payment, like scheduled payment.
5
Design Tik Tok / Instagram Reels
5
Design Machine Learning Systems
5
Design Gmail/Outlook
Email service
5
Design skyscanner
Given a service that returns flight deals for the last 7 days, design a system that surfaces relevant flight data to a user and notifies the user when there’s a new flight that matches their criteria
5
Deep Dive - RabbitMQ
5
Deep Dive - ZooKeeper
5
ML System Design Examples
Please include some ML System Design Problems as well.
4
Design Quora/Reddit
4
Design Stadia like gaming service with top player leaderboards
Imagine that Youtube team would like to start advertising games before video begins. The ad will allow you play for 2 minutes and offer a link to purchase a game after that + leaderboards. Can you succeed where Google failed?
4
Design a distributed auto increment id generator(should be ascending order)
4
Web Crawler
Design a webcrawler
4
Job Scheduling
Design a scalable job schedulable that can schedule jobs in a perodic mannner
4
Design a centralized notification system
A social media app sends multiple notification to users. Different notifications are owned by different teams. Create a system which will be used by various team to send notifications immediately or in future.
4
Design Coding Contest Platform
4
photo sharing app like Instagram
4
Design amazon locker
4
Design of Amazon Product Review System
Design of Amazon product review system, write and read part especially during sale periods
4
Phising detection system
Design a phising detection system
4
Phising detection system
Design a phising detection system
4
Design Google sheets
4
Design Shopify
4
Design a chat app
Design a chat app that support instant messaging (1-1, group chat).
4
Design a file system
Design a file system that can store 100s of PB of data. It offers POSIX semantics.
4
Design an ad serving system
Design a real time ad serving system for digital ads
4
Deep dive data warehouses
4
Design Zoom
4
Tag service
4
Design Realtime analytics dashboard
4
Design BrowserStack
Executing UI tests in multiple browser instances concurrently.
4
design a instagram
Upload, view posts able to send images and videos
4
google maps
4
E commerce
4
Design Live video streaming platform
System like hotstar which streams worldcup matches for 10 M users concurrently
4
Design TrueCaller
4
stock exchange
4
Design Facebook Live
Design a service to host a live streaming platform which can be used by anyone to broadcast live video to millions of users.
4
Memcached vs Redis vs VoltDB
Dive deep into the choice of cache
4
Spotify
4
a feed aggregator
Create a feed aggregator that collects all social media into one combined feed
4
Design S3 Blob Storage
4
Design online multiplayer game
4
Design chess
4
Find shortes path between 2 users on linkedin.
Given 2 user IDs of users on linkedin. Find shortest path between the two. Assume that the shortest path won't be more than 4. This is similar to 1 degree 2 degree and 3 degree connection in linkedin.
4
Design logger
4
Deep Dives
Kafka vs RMQ when to choose
4
Invetory tracking/management system
4
Deep Dive - What happens when you search google.com
A deep dive into the flow of how DNS are converted to IP and common networking related data.
4
design hotel reservation system
4
Design a Blob Store Lile AWS S3
4
Design Zookeeper service
4
Desing Location based Restaurant Recommendation
4
observability tool like datadog
4
design an audit/event logging system
similar to pg_stat in postres. users should be able to find tables/columns used in time period. system should tell which columns/tables have not been used in time period t.
4
Design authentication-authorization requests pipelines
System design - scale authentication-authorization requests pipelines for third-party vendors
4
Design stackoverflow
Design a Q&A platform like StackOveflow where users can ask questions, provide answers, upvote content, and earn reputation points
4
Design ATM
Basic ATM functionalities: Withdraw cash and update balance Deposit cash and update balance Check balance Deposit check and update balance Change PIN Update email, mobile number
4
Design Shazam
4
Design Cloudwatch
4
Design an IDE
Build a coding platform like intelliJ or Xcode that offers CI/CD, code editor, deployment automation tools, simulator, and supports multiple coding languages
4
Deep dive - CDN
4
Design GoogleMeet
Online realtime video conferencing tool
4
slack
4
Design Twitch
Live streaming platform
4
Design Amazon price notification system
4
Design chess.com or lichess.org
Design a system similar to chess.com (or lichess.com), which supports online chess games between users.
4
Deep Dive - Sharding
4
Design Instagram reels
4
Design Facebook/Instagram privacy
4
CDC - Implement Change Data Capture
4
Online Review System for food delivery app
Design a feature that accepts reviews from customers for an item orderded in a food delivery app. Also, show the average rating so far each item under a restaurant.
4
Design Cloudflare
4
Design Reddit Comments
4
Design Hello Interview
4
design webhook
4
Design orchestration
3
Klarna System Design
3
Design wikipedia
3
Design Whatsapp or Facebook Messenger
3
Design IFTTT
3
Design a messaging queue like Kafka
3
Design youtube shorts
3
Design ACL like Notion
In Notion ACL can be implemented on individuals, group of individuals as well as on pages where if a user has access to parent page then the user also has access to all the child/nested page.
3
sentry.io
Design a sentry.io like system
3
Continuous Integration System
3
Views and likes of a post in twitter(X)
Design a scalable system to handle the millions of views and likes of post in twitter. We should be able to scale for both read and write
3
Design Zillow
3
Online Stock brokerage
3
Typo
Handling Big Data and Real-Time Web Apps: You have an applications dealing with large volumes of data, especially unstructured data, or applications requiring real-time data processing and analytics. an applications is wrong
3
Design a telemetric service
All the services that are deployed in a organization can send their such as cpu/memory/ etc. These information can also be used by alerting/alarming service to alarm
3
Design a ledger system
common question for fin tech, design a ledger system can record money movement and account balance.
3
Design Block Storage System .
I was asked this question within Amazon . The question is "Design a block storage system that can reduce the fragmentation of the disk and provide durable storage devices on demand" . Something like AWS Elastic Block Storage.
3
Design Stripe/Plaid
3
Open AI
3
Internal company tool
placed in charge of a large application - runs in a single data center - all stored there and all processing serving and traffic is done there -multi data store -multi app server - serving diff portions of app design tool to monitor performance
3
Design Snapchat
main requirements : 1. sending of snap to one another/group 2. stories 3. snap score
3
Compiler
https://www.reddit.com/r/leetcode/s/9u0xAKryPI
3
Design a Bookkeeping System for Tracking Personal or Business Financial Tra
A bookkeeping system is used to record and manage financial transactions, such as income, expenses, and transfers. It helps individuals or businesses keep track of their financial activities, generate reports, and ensure accurate financial management
3
Design Common Components
Basically multiple design questions that explain how to design MQs or Blob Stores or Rate Limiters or Load Balancers...etc common components we would use in product design questions
3
Distributed File Transfer System
- Get one large file to thousands of servers in short time - System design specifically focused for Production Engineering role at Meta
3
Production Engineer System Design
- Design Problems asked in production engineering role - Doing OS upgrade in scale, automation etc
3
Metrics Monitoring and Alerting system
Metrics Monitoring and Alerting system
3
Distributed counter
It has many use cases like: 1. Count of unique concurrent users logged in to a system 2. Count of a particular doc opened by user. 3. Count of likes on a post. The count value should be near real time.
3
Collabarative text edit like GoogleDoc
- collabarative text edit - simple styling - different type of clients
3
Design GitHub
Repositories' version control system
3
Design LRU Cache
3
Design Instagram story
3
Design Online Multiplayer Gaming Platform
3
Design Skype/Facetime
Design a service for the video call or conferencing between 2 or more users.
3
Design a zero-downtime data migration system
Intrigued by the logical replication section in the PostgreSQL deep dive, it would be interesting to see how data migrations are done at scale.
3
Design like .mint app
3
Design TikTok
3
Design Alexa
3
Design a Google Calendar
3
Deep Dive Kinesis
3
Design Instagram Stories
Similar to designing something like a Facebook News Feed, but this time with handling photo uploads, story curation, and timing out / expiring of stories after some specified time.
3
Design a mobile image search client
3
Design a memcache
3
Design a Parking lot
3
Weather app
3
Data modelling for system design
Writeup/ video on how to properly create a data model for your system
3
Design weather app
3
Design a system to store images for FB and instagram that would require 100
3
Design perplexity
3
Design Kafka
3
Citi Bike
Design a bike sharing service like Citi Bike which could include the maintenance and docking stations
3
Design backend of food delivery app like Doordash
3
design kubernetes
3
Design OneNote/Google Keep
Sync notes across different clients Live editing & collaboration
3
Design a poker game
You're an online Casino offering some subset of gambling games to a large set of users. How would you design a system to support a wide variety of users, protect against fraudulent activity, and handle different types of regulatory constraints?
3
Design Datadog or equivalent
3
Design Just the UX and APIs for Newsfeed
3
Design Instagram Stories
Challenges in this particular problem: - Ephemeral - Ordering stories(latest first) - Paging for clients
3
Design Event Tracking System like Amplitude
Create a scalable system for collecting, processing, and visualizing user event data. Include SDKs, reliable ingestion, efficient storage, querying, chart rendering, observability, error handling, and scalability.
3
Design a System for Event Processing and Querying
Build system to ingest, process, and store events (e.g., clicks). Support queries like histograms of clicks/hour over 24 hours. Ensure low latency, high availability, and design an SDK to handle server unreachability and traffic spikes.
3
Deep Dives: Apache Pulsar
3
Design Kubernetes
Design a container orchestration system for automating software scaling
3
Design a Large-Scale Image Rating Platform
Design a system where users rate images from a pool of 1M+ images. Each image needs configurable minimum ratings, no duplicates allowed. Focus on rating distribution, cost efficiency, scalability, and reliability. Handle spam prevention.
3
Deep Dive - ScyllaDB
3
Design Coursera
3
TRANSIT CENTER : MANAGEMENT
3
Embedded system design for wifi team
My background is wifi. I would like to know about some system design ideas about the embedded system design.
3
We list products and want to calculate sales and see top products sold ever
these are open ended questions which are asked
3
Instant web search
Design an instant web search engine like G Instant.
3
Suggestion for Azure alternatives
I appreciate the valuable content, especially with AWS. It would be incredibly helpful if Azure equivalents were also included. This would support folks working with Azure and create a more well-rounded resource for all. Thank you for considering!
3
Design an HTTP interpreter for a web browser
3
Design a distributed linked list.
3
S3 Deep Dive
Would be nice to have a S3 Deep Dive, especially how to use S3 for object storage and use it at scale.
3
Design Amazon
3
IoT Cloud
Large-scale infra for handling, collecting minimum 10 million devices data. For example building Connected Cars system using MQTT, Kafka, etc. Like any kind of devices can be registered and push the data to this cloud. Examples HiveMQ, EMQX, VerneMQ.
3
Pastebin
3
How do you handle localization
Currently, on the server side, we have the below logic to handle localization. How do you scale up this switch title case "en-US" return "Welcome to Facebook"
3
Design reddit
3
HTTP concepts relevant to system design
HTTP is a broad topic with plenty of content available. But, we see it dropped in guides on HelloInterview: where to put sensitive data? When to use headers? When to use PATCH?
3
Design a RAG application
3
Distributed Job Scheduler - Kindly make it public
3
Design an event scheduler
Design a system for managing patient appointment scheduling, allowing for complex booking options (e.g., recurring appointments, multiple provider types, flexible cancellation policies)
3
Design "Find My iPhone"
Functional Req: To be able to report my location To be able to see the location Max allowed lag 30 seconds Worldwide system 1B daily requests Follow up: "can you do (and should you) it with web sockets?" "dive deep into the DB design choices"
3
design chatbot
3
Design Fuzzy search feature
3
Design Capcut
Design a video editing/manipulating service
3
Github Actions
Design a system like Github Actions which can run tests/actions in a scalable/configurable way.
3
Design Waze
Design a real-time navigation system like Waze that provides optimal route planning by considering live traffic conditions, user reports, and GPS data.
3
Design a buy now pay later (BNPL) service
A service similar to Affirm where users can pay for their purchases over a specific time period.
3
Design TTL from scratch
How would you implement a Time To Live at scale from scratch?
3
Design a File system that syncs files across devices
Users should be able to create, update and delete files and sync across devices
3
Likes counter
facebook/instagram distributed likes counter
3
Product vs Infra difference in meta interviews
messaging system 2 Design something similar to Instagram reels. Design Instagram upload and feed service 2 Design Leetcode Judging System 3 cloud sharing Top k frequently played songs for an apple music like service.
3
Design Nearby Friends
Design a system which has an option to view Nearby Friends like in Snapchat
3
Design Uniswap
Design a decentralized exchanged (DEX) for buying and selling crypto
3
Amazon catalog page/ shopping site
Would be great to know the best design for this highly asked question
3
HLD Design Patterns
Common Design patterns used in microservices
3
Scaled data pipeline and crawler for AI models
Design a planetary scale capable data pipelining and crawler product that’ll collect data of the internet to improve home grown Llm model and also handle novel problems like efficiency in not taking similar content, synthetic data generation
3
Design LinkedIn Recommendation System
(1) A user should be able to ask for recommendations under various relationship status between requester and giver (2) A user should be able to give recommendation (3) A user should be able to see what recommendations other users have got.
3
Dive deep authentication/authorization
3
Design Restaurant Reservation System
Design a restaurant reservation system which will handle booking as well as sending reservation reminders.
3
Scheduling Payment service
transaction is taken care by wallet service but initiating and scheduling payment needs to be taken care by the system
3
Design a HR/Payroll system for employee onboarding
3
System Design Distributed Locking
3
Design a video security system.
- Customer can will live/recording remotely - Camera can send alerts to customer if certain "physical" rules are violated - Customer can search video via keywords (Assume AI pre-process it)
3
Design App/Play store
3
Deep Dive - Temporal
3
Deep Dive - Recommender Systems
3
Flink Deep Dive
3
Design Recommendation Page of Instagram
Design Recommendation Page of Instagram which has explore and search
2
Design an AI Agent
An artificial intelligence (AI) agent, or a system that can autonomously perform tasks on behalf of a user or another system.
2
deep dive message queue
kafka vs rabbitmq vs zeromq vs sqs vs activemq when we should use each of the above with concrete use cases
2
Deep dive on commonly used AWS sevices
deep dive on S3, AWS Lambda, Cloud watch and other important and commonly used AWS technologies
2
Design venmo
2
Real Time Stock Price API
2
Design a location based service like Yelp
2
Get active events
System has handlers set_start(id, ts) and set_finish(id, ts). Incoming data via these endpoints are quite high. The finish event can come before the start event. What's the optimal way to calculate getActiveEvents(ts)?
2
Design Global Counter
2
Design a therapy booking platform
like betterhelp or growtherapy
2
Design a build service for multi region cloud
2
Design youtube likes
Users see likes on videos with low latency
2
design online Pong Game
players can join, and need to be matched with someone else who is online
2
Design a virtual agent
Design a virtual agent (retail/commerce/etc) which interacts with customers from a web or any other interface to understand the customer's questions and respond based on the company's or org's knowledge repository and any off the shelf LLMs (RAG)
2
Design Talent assessment platform & a resume screening/tracking system
Design Talent assessment platform like hirevue and a resume screening/tracking platform.
2
Design a Reminder application
2
Design a Traffic Light Control System for a city
2
Below looks not right. Could you confirm
Message Ordering: However, some queues (like Kafka) allow for more complex ordering guarantees, such as ordering based on a specified priority or time.
2
Design a hotel aggregator system where user can book a room
2
Design a social media application for introverts.
2
Design code coverage tool
2
Design a centralized video update management system
Design a centralized video update management system that integrates with mu
2
Design figjam with multiplayer support
Figjam with comments and comment replies, with real time updates
2
Design Telegram - support for large group chats
2
Designing a URL Shortening service like TinyURL
2
Design a Connector between Tiktok to its vendor like Amazon/Shopify
2
Design a Currency Converter
2
Distributed Key Generation Service
A system to support idempotency transactions.
2
Design VirusTotal
Users can upload file(s) to be scanned by multiple anti-virus engines and metadata scripts. Provide results close to real-time as possible. Scale to millions of users.
2
Stock Broking System
- Frequent update stock price which will reflects on Millions of end users - Order execution partially or fully - Event base order executions like Stop loss
2
Ebay Auction Site
Highly consistent, low latency and scalable system
2
design payload
2
Design an online multiplayer game system
2
Metrics Agrregation system
2
Design Fandango
Design backend for Fandango which provides functionality to book tickets with multiple providers. How do you manage locking?
2
Design clubhouse
Design a service to host audio conferencing between people for a scheduled event.
2
Design Message Broker like Kafka
2
Design a proximity Service
2
Design a counter service
2
Design a sports betting Platform
Like Kalshi/Polymarket/BET 365
2
Design a cash/points back e-commerce aggregator system
Like LINE Shopping, Shopback
2
Design a vulnerability scanning platform
design a platform that we can updload different sources (binary, image, sbom, and container) to be scanned and generate vulnerabilit report to triage vulnerabilities to related teams.
2
Design online multiplayer game
2
Design card balance notification system
If balance drops below threshold notify user
2
Design a logistic management system
Design a logistic management system like UPS, focusing on package CRUD, routing and tracking.
2
Telemetry Service
Process data from IOT
2
Design Facebook Status Update & Search
User is able set a status. 1 Status only per user. Design a third party api that can do a search on the status update.
2
discord
2
Design Moovit (Transportation App)
Design a real-time public transportation app like Moovit that provides users with the best routes by combining static schedules and live GPS data, including multimodal transport (buses, trains, metro, etc.).
2
Design Moovit (Transportation App)
Design a real-time public transportation app like Moovit that provides users with the best routes by combining static schedules and live GPS data, including multimodal transport (buses, trains, metro, etc.).
2
Design a file deduplication service
Design a service that does file de duplication
2
Design google drive
2
Design Unique ID generator in Distributed systems
2
Design Distributed Email service
2
Deep Dive on Blob storage
We are using and also referring to Blob storage that too Amazon S3 a lot. It is better to have a little understanding on it.
2
Please update content of DSA practice problems for java language.
2
LLD Interview Guides
2
Technical Project Retrospective
Please orient us to what this interview is "all about" with a helpful video or information page.
2
Design Google Stadia Cloud Gaming
2
Design Perplexity
Perplexity uses LLMs, Retrieval-Augmented Generation (RAG), and cloud-based infrastructure to deliver accurate, real-time answers with citations. It prioritizes scalability, transparency, and a user-friendly conversational interface.
2
Database internals
Deep dive into data storage internals, indexes, transactions and other important DB concepts.
2
Tag Management System
Design a Tag Management System to tag assets of different types (emails, documents, photos, etc) with millions of user-created tags. It must support efficient retrieval of assets per tag, and popular tag identification.
2
AWS Step Functions Deep Dive
2
Networking Basics | VPCs/Routers/Route53/etc.
2
Auth for File Sharing App
x users have auth to read 1 file. y users have auth to read 2 files. z users have auth to read folder. Google Zanzibar
2
Google Zanzibar Deep Dive
2
gRPC
2
Design orchestration engine like K8s
An orchestration engine for containerized applications or pods like K8s.
2
Deep Dive Debezium
2
Deep dive Redshift
2
Flight Radar 24
FlightRadar24 is a real-time flight tracking system that ingests ADS-B signals from aircraft, aggregates data from multiple sources processes it for live tracking, and serves it via a scalable API and web interface, ensuring low-latency.
2
Design A centralised software update system.
Design a centralised update system where servers can update to latest softwares and software owners can upload latest softwares.
2
Design Amazon
An online shopping store at scale
2
Design Hinge Dating App
2
Design weather app.
Design a weather app which ingests data from third parties.
2
Design IoT Sensor Data Aggregator
2
More ML Engr Q's
Design a product recommendation system ("Design Amazon Homepage", "Design Etsy Homepage") Design a personalized news ranking system ("Design NYT Homepage", "Design Barron's Homepage") Design an evaluation framework for ads ranking
2
Design Real Time Gaming Leaderboard
A real time gaming leaderboard which shows ranking and score of the players, used in many gaming apps like clash of clans, fortnite and pubg
2
Design Anduril
2
Design DoorDash
2
Explain Saga Pattern Deep Dive
Saga Pattern to handle distributed transaction.
2
Design tagging system
Multiple services such as atlassian jira, confluence and gitlab store tags. This is the most frequently asked question in atlassian
2
Design a distributed database (Infra)
2
Design Real Time Bidding system
RTB processes millions of ad requests from publishers. Each request is sent to multiple DSPs, which analyze user data and bid. RTB selects highest bid, and the winning ad is sent to the publisher. All steps must completes less than 500ms.
2
Mobile System Design
For Android & iOS SD interviews. Such as Chatting App, Twitter home page, etc
2
Deep Dive - OLAP databases
How OLAP databases store data, column compression, aggregation etc.
2
Distributed Search Engine
A search engine similar to google / Bing search
1
Deep dive on AWS Lambda
To effectively use AWS Lambda and address cold start trade-offs, focus on its scalability and cost-effectiveness benefits.
1
Improve "Design WhatsApp"
Go deeper earlier in the design to allow for "actual" deep dives during the deep dive. Or keep current HLD but improve/add deep dives
1
Design Credit Card Application
1. user should be able to submit application, our system should take decision 2. user should be able to create online account and add their cards 3. user should be able to make purchsases and our system will process payments 4.analytics
1
Design UberEats/DoorDash
Fetch the menu for 50,000 users per second Fast menu updates (availability of products)
1
Design Low Latency Stock Exchange (not broker)
1
Time Series Database
Design Systems with time series database
1
Big Data Processing
Design Systems with Batch processing (DAG order)
1
scalable monitoring system
To design a scalable monitoring system for a million hosts with 10-second status checks and real-time reporting, follow this architecture:
1
Design a File Recomendation system
1
Free food/burger app
Design a system to distribute 6 million free burgers in 10 minutes, ensuring each participant receives no more than one burger, while handling over 20 million requests during this period.
1
Design Microsoft Teams
- Design Microsoft Teams
1
Design a system that can hack a website (FB Messenger) and scan pages/mess
1
Ads recommendation Engine
1
Code Review Interview
Code Review Interview that's found in Google L6 EM and Meta final round interviews.
1
Design GoFundMe
1
Design Chat Assistant
Design a chat assistant which responds with prompts, and connect to a live agent if needed
1
Notes taking feature
I want to use hello interview website to take notes of any new system designs I learn or any new thing I read. Can you provide a option to link exalidraw with hello interview.
1
Deep Dive - RDS Aurora
Aurora offers all the advantages of PostgreSQL/MySQL with built-in vertical and horizontal auto-scaling, replication, failover, and high availability out of the box.
1
Leveled Feedback
The user should specify the level that they're interviewing for (mid, senior, staff+) to the guided review feature. The guided review feature should use that targeted level to give feedback relevant to level of the interviewee.
1
Redo Top K
1
Design Perplexity
1
Design Market Data FeedHandler
Assume you are designing a Market Data pipeline of a big company that uses the financial data to make market making decisions. You need to design a consumer of external data, normalise it, store the headers from the data and distribute it downstream
1
Design a distributed tracing system (e.g zIpKin)
1
Design an A-B testing system (Similar to Optimizely)
1
Design Venmo
1
Design anonymous app like Blind
- user registration can only happen through certain emails - user allowed to change user names - backend will not store email - if user forgets password, they cannot login
1
Deep Dive: RESTful API design best practices
- Structure (header, body, parameters and so on) - Naming conventions - When to use PUT/PATCH/GET/PUT - How is the call secured: Encryption level in header, body, Authorization and Authentication, Rate limiting - Passing sensitive information
1
Design a Product Analytics Platform like Google Analytics
- A platform that gives insights to the customers about the user actions on a website (like amazon). - Provide realtime insights as well as ability to drill by multiple dimensions to get information about critical KPIs
1
Deep dive - SQS
Deep dive on AWS SQS
1
Deep dive - S3
1
Scaling a system
What are the different patterns to keep in mind while scaling a system? A write up about this would be great. Thanks
1
Design Facebook TAO
Design Facebook Social Graph at Scale: TAO (The Associations and Objects)
1
Dropbox Google Drive - II (With file sharing and version control)
the last video was really amazing but it would be amazing to see how version control, file sharing, concurrent updates could be added to the system
1
Config Management System
Design a configuration management system - Users should be able to add, delete or search for configuration - Users should be able to subscribe to configuration and get updates if there are any updates to this configuration
1
Google Translate
1
When to use what database?
Can you please create a write-up about when to use what database based on certain example scenarios and why? Like Sql vs Nosql, for high writes vs high read throughput. Also, what dbs can work similarly? - eg. Dynamo and Cassandra
1
Design CI/CD
1
Design an Inteference Platform
1
System Design of a Scalable Multiplayer Real time chess game
Saas based Chess game like lichess or chess.com
1
Restaurant Order Aggregation System (Otter POS)
Create a restaurant order aggregation system such as Otter POS. Restaurants can run Otter on a device and see all the orders from marketplaces such as Doordash, UberEats, Grubhub etc. Other capabilities included are menu, inventory management.
1
Design Instacart
Design an online delivery service that allows you to shop for groceries and other items from various stores (grocery stores, wine shops, etc.) and have them delivered to you by a personal shopper
Schedule a mock interview
Meet with a FAANG senior+ engineer or manager and learn exactly what it takes to get the job.