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System Design HLD Example: Web Crawler

Mar 28 · 9 min read · ≡ƒôû What a Crawler Is Actually Doing: Use Cases and Actors ≡ƒöü Flow This section illustrates the high-level read and write flows for the system. The diagram below shows the main components and the sequence of messages for the primary user journeys....

System Design HLD Example: Video Streaming (YouTube/Netflix)

Mar 28 · 33 min read · ≡ƒôÉ Complexity & Section Matrix (Author Reference ΓÇö Not Published) SectionBeginnerIntermediateAdvanced TLDRΓ£à RequiredΓ£à RequiredΓ£à Required ≡ƒôû What is [Topic]?Γ£à RequiredΓ£à RequiredΓÜ¬ Optional ≡ƒöì Basics of [Topic]Γ£à RequiredΓ£...

System Design HLD Example: Ride Sharing (Uber)

Mar 28 · 38 min read · TLDR: A ride-sharing platform is a real-time geospatial matching system. Drivers push GPS location every 5 seconds into a Redis geospatial index. When a rider requests a trip, the Matching Service runs a GEORADIUS query to find nearby available drive...

System Design HLD Example: Proximity Service (Yelp)

Mar 28 · 34 min read · ≡ƒôû Why a SQL Range Query Can't Find Your Coffee Shop Actors and Use Cases ActorRole Mobile User / CustomerSearches for nearby businesses or services; submits reviews Business OwnerRegisters their location and manages their listing (name, ad...

System Design HLD Example: Real-Time Leaderboard

Mar 28 · 32 min read · ≡ƒôû Use Cases and Actors: What a Real-Time Leaderboard Must Do Actors ActorRole Player / UserSubmits scores and views their rank Game / Event OwnerCreates leaderboard events and manages scoring rules Viewer / SpectatorBrowses global and fri...

System Design HLD Example: Distributed Job Scheduler

Mar 28 · 41 min read · ≡ƒôû What a Job Scheduler Must Coordinate: Actors and Use Cases Actors ActorRole Job Submitter / DeveloperCreates and schedules jobs via API or UI Job Executor / WorkerThe compute node that picks up and runs scheduled jobs ΓÇö an external con...

System Design HLD Example: Hotel Booking System (Airbnb)

Mar 28 · 32 min read · ≡ƒôû The Double-Booking Problem: Two Guests, One Room, One Disaster Actors ActorRole Guest / TravelerSearches availability, books rooms, and manages reservations Hotel / Property ManagerManages room inventory, pricing, and availability calend...

System Design HLD Example: News Feed (Home Timeline)

Mar 13 · 19 min read · ≡ƒôû Use Cases Actors ActorRole Publisher / AuthorCreates and posts content that fans-out to followers Reader / FollowerConsumes the home feed of followed users' posts; expects fresh results in < 100ms Content ModeratorReviews flagged conten...

System Design HLD Example: Notification Service (Email, SMS, Push)

Mar 13 · 18 min read · ≡ƒôû Use Cases Actors ActorRole Notification Sender / ServiceTriggers notifications via API (e.g., payment service calls POST /notifications) End User / RecipientReceives push notifications, emails, or SMS on their device Admin / OpsManages ...

System Design HLD Example: Chat and Messaging Platform

Mar 13 · 19 min read · ≡ƒôû Use Cases Actors ActorRole Message SenderInitiates and sends text/media messages; expects immediate confirmation (sent tick) Message RecipientReceives messages and reads conversations; WebSocket push or push notification fallback Group ...