Master Low Level Design

Explore LLD Problems

A curated collection of common Low Level Design interview problems.
Learn patterns, practice modeling, and ace your machine coding rounds.

Design a system which keeps track of leaders for some contest. Like referrals leader.

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Design Chat Based application like whatsapp/wechat.

Design Game Streaming platform.

Design message queueing system

Design system for short video/content sharing like Tiktok.

Design the Food Ordering System like Swiggy/Zomato.

Notification Service design.

Design a distributed Cache.

Design a scheduler, that takes in 10 scheduling requests at a time and can execute 100 jobs at a time.(The scheduler executes http requests.)

Design a user activity tracking system for user on mobile.

Design a UUID generator.

Design Ads system for a website.

Design Car Rental System like Zoomcar.

Design Community based discussion platform.

Design push notification :

Design Real time collaboration application for the teams.

Design Splitwise.

Developing a message queueing system.

Design System Simiar to the Product-hunt (share and discover new products)

Design a Cache Mechanism.

Design a suggestion system

Design Authentication/Authorization Service which supports(otp,OAuth, etc.).

Design Chess Game.

Design Inventory System.

Design monitoring and alert system for the production as well and other enviroments.

Design Short Story Telling (Text/Images) platform like Terribly Tiny Tales.

Design Splunk like log manager system supporting queries with filters on last min, hr, day, week etc.

Implement a wide column store like Cassandra (bonus : support secondary indexes).

Create an online music recommendation system which suggests songs according to user taste.

Design a billing and auctioning system similar to EBay.

Design a calendar Application (similar like Google Calendar)

Design and Architecture - Appointment booking for a hospital where each doctor can open slots independently of any time period.

Design LinkedIn.

Order-Management-System-or-System-Design.

Build the Google Stock Wizard.

Design a stock exchange system. There is a list of stocks given with following attributes

Design Logging Framework

Design Navigation Alerts System. (Similar like Google Map Functionality.)

Design Real-Time Translation platform.

Design subscription-based sports website which can display scores, game status, history for any games.

Design Truecaller.

Design a generic coupon/promocode system.

Design a Logistics System

Design a scalable weather service that pulls data from an API.

Design an concurrent History tracking system where we can store and track history of registered entities. We should be able to onboard service and their entities to our system and start tracking

Design for online card game say like poker or any other game.

Design Freelancing hiring platform.

Design library management system.

Design Virtual Event Platform for Communities / Enterprise.

code a TextPad with following functionality:

Design Amazon comments filtering system

Design Payment Gateway like Razorpay.

Design pricing / product comparision system.

Design Q&A application as in Amazon,Walmart has it for each product.

Design system for salary info,comparsion and other info similar to the glassdoor salary / salarry.level.

Design Visual workplace for remote teams.

Implementation of Kafka.

Design a Plagiarism checker.

Design an online code judge.

Design application for restaurant / malls to efficiently handle waiting queue and optimizely assign the table.

Design job posting system dedicated to blue and grey collar workers. (multiple langs / native lang)

Design Mock Interview System like pramp.

Design Online UML Diagram Tool like lucidchart.

Design service like Clipboard. (try to store the maximum clips)

Design User Engagment platform.

Design a geographically partitioned multi-player card game, that supports multiple players, multiple games at a time.

Design a system like Jira. It should have the following functionalities :

Design product experience platform like pendo.

Design Secure Content Management platform.

Design Survey similar to Google Forms / SurveyMonkey.

Design a electronic signature system like DocuSign / EasySign.

Design a locker

Design Learning Management System

Design Maps Navigator Client for different transportation types

Design Online Exam Portal.

Design a configuration management system

Design a Vending Machine

Design Application Tracking System (ATS) like greenhouse

Design of a quizzing app.

Designing a ID card system which employees use to access any zone/premises.

Design a home automation sytem to remotely control all the switches, devices in a home.

Design a limit order book for trading system.

Design online audio/video file downloader.

Design Warehouse Management System.

Design Employee Management Platform which includes payroll,IT,employee benefits and all other employee operations in one place.

Design Guitar Inventory System

Design online customer verifaction platform for digital on-boarding(KYC) of the users for bank and others client's.

Design Unit Testing Application

Design a torrent service, end to end.

Design Browser testing Application like browserstack / sauce labs.

Design digital-video KYC (know your customer) verification system.

Gym Managment System.

Implement a finite state machine.

Design a Json Parser from scratch

Design a system which improves the quality of the data.

Design a business rule based engine.

Design CSV parser

Design online e-fiiling online income tax returns service.

Design a Bar Graph Library.

Design a Jackpot Machine.

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Design and Implement a Simple Java GC (Java 7+)

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Airline Seat Reservation System

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Design a login API which is secure even if SSL certification is compromised.

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Design a personal stock / investment protfolio system.

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Design a service for showing HeatMap of Swiggy / Zomato agents at a time.

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Design a service that calls any passed endpoint at a fixed interval.

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Design a service to view/add/remove viewers of a document (like the feature in google doc).

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Design a SMS validator system.

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Design a stock trading system

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Design a system (initially one node/server) that could handle requests on the scale of millions. It should return a unique id for each request (The id should be unique in sense that there would be o

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Design a URL Shortener with Collision Handling and Analytics

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Design a video upload system for a user with low network bandwidth

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Design an analytics to display machines which have valid certificates,Design the system with valid dashboard with all the machines with good/bad certificates.

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Design an Online Auction.

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Design and Develop the Zookeeper using Rocksdb and Google's BigTable.

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Design and Implement Rocksdb.

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Design for storing chemicals with their constituents in an efficiently retrievable format.

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Design in-memory (Questions like write to add,remove the table,etc).

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Design Learning app (Design system where teachers can upload the content and stuedents can view that content.)

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Design Linkedin Suggest connections feature.

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Design Live Auction platform for IPL / EPL.

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Design online assesment platform for exam's like gre / tofel.

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Design system like Bigbasket (local retailer's).

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Design System where User can create alerts on StockOptions.

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Design system which exposes two APIs:

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Design the Bill Summary Feature.

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Design Webhook Dispatcher.

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Design(HLD) Zipkin - A request tracing system for distributed applications. Example - A request is flowing through multiple microservices, system should be able to trace the time spent by the reques

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Desing Payment System

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How to design an API whose response will have the response from 3 other different microservices.

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Implement service to Find the recently viewed listings on the website by the user. Example a user looked for hotels in Bangalore. Design a system responsible to return the recent listings for a user.

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Unix File Search Engine

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You are required to implement an in-memory cache module/library which you will embed in your application to improve the application performance, by holding heavily accessed (read/written) application

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Explore LLD Problems

Design Parking Lot.

Design an API rate limiter.

Design an Automated Teller Machine (ATM) System

Design a key value store and an Index.

Design a system which keeps track of leaders for some contest. Like referrals leader.

Design Chat Based application like whatsapp/wechat.

Design Game Streaming platform.

Design message queueing system

Design system for short video/content sharing like Tiktok.

Design the Food Ordering System like Swiggy/Zomato.

Notification Service design.

Design a distributed Cache.

Design a scheduler, that takes in 10 scheduling requests at a time and can execute 100 jobs at a time.(The scheduler executes http requests.)

Design a user activity tracking system for user on mobile.

Design a UUID generator.

Design Ads system for a website.

Design Car Rental System like Zoomcar.

Design Community based discussion platform.

Design push notification :

Design Real time collaboration application for the teams.

Design Splitwise.

Developing a message queueing system.

Design System Simiar to the Product-hunt (share and discover new products)

Design a Cache Mechanism.

Design a suggestion system

Design Authentication/Authorization Service which supports(otp,OAuth, etc.).

Design Chess Game.

Design Inventory System.

Design monitoring and alert system for the production as well and other enviroments.

Design Short Story Telling (Text/Images) platform like Terribly Tiny Tales.

Design Splunk like log manager system supporting queries with filters on last min, hr, day, week etc.

Implement a wide column store like Cassandra (bonus : support secondary indexes).

Create an online music recommendation system which suggests songs according to user taste.

Design a billing and auctioning system similar to EBay.

Design a calendar Application (similar like Google Calendar)

Design and Architecture - Appointment booking for a hospital where each doctor can open slots independently of any time period.

Design LinkedIn.

Order-Management-System-or-System-Design.

Build the Google Stock Wizard.

Design a stock exchange system. There is a list of stocks given with following attributes

Design Logging Framework

Design Navigation Alerts System. (Similar like Google Map Functionality.)

Design Real-Time Translation platform.

Design subscription-based sports website which can display scores, game status, history for any games.

Design Truecaller.

Design a generic coupon/promocode system.

Design a Logistics System

Design a scalable weather service that pulls data from an API.

Design an concurrent History tracking system where we can store and track history of registered entities. We should be able to onboard service and their entities to our system and start tracking

Design for online card game say like poker or any other game.

Design Freelancing hiring platform.

Design library management system.

Design Virtual Event Platform for Communities / Enterprise.

code a TextPad with following functionality:

Design Amazon comments filtering system

Design Payment Gateway like Razorpay.

Design pricing / product comparision system.

Design Q&A application as in Amazon,Walmart has it for each product.

Design system for salary info,comparsion and other info similar to the glassdoor salary / salarry.level.

Design Visual workplace for remote teams.

Implementation of Kafka.

Design a Plagiarism checker.

Design an online code judge.

Design application for restaurant / malls to efficiently handle waiting queue and optimizely assign the table.

Design job posting system dedicated to blue and grey collar workers. (multiple langs / native lang)

Design Mock Interview System like pramp.

Design Online UML Diagram Tool like lucidchart.

Design service like Clipboard. (try to store the maximum clips)

Design User Engagment platform.

Design a geographically partitioned multi-player card game, that supports multiple players, multiple games at a time.

Design a system like Jira. It should have the following functionalities :

Design product experience platform like pendo.

Design Secure Content Management platform.

Design Survey similar to Google Forms / SurveyMonkey.

Design a electronic signature system like DocuSign / EasySign.

Design a locker

Design Learning Management System

Design Maps Navigator Client for different transportation types

Design Online Exam Portal.