System Design: Distributed Counters, Leaderboards, and Real-Time Analytics
6 min read The Problem: Counting at Scale Incrementing a counter sounds trivial — until you need to count 10 million page views […] Read article
System Design
System Design
System Design: Collaborative Document Editing (Google Docs) — OT, CRDT, and WebSockets
7 min read The Problem: Concurrent Edits In real-time collaborative editing (Google Docs, Notion, Figma), multiple users edit the same document simultaneously. The Read article
System Design
System Design: Distributed Task Queue and Job Scheduler (Celery, SQS, Redis)
7 min read What Is a Distributed Task Queue? A distributed task queue decouples work producers from work executors. Producers enqueue jobs; workers Read article
System Design
Low-Level Design: Food Delivery Order System (DoorDash/Uber Eats) — State Machine, Driver Assignment
7 min read Requirements Functional: customers browse restaurants and place orders, restaurants receive and confirm orders, the platform assigns delivery drivers, drivers pick Read article
System Design
System Design: Apache Kafka — Architecture, Partitions, and Stream Processing
7 min read What Is Apache Kafka? Apache Kafka is a distributed event streaming platform built for high-throughput, fault-tolerant, real-time data pipelines. Unlike Read article
System Design
Low-Level Design: Subscription and Billing System (Recurring Payments, Proration, Retry)
8 min read Requirements Functional: subscribe/unsubscribe users to plans, charge recurring fees at billing intervals, support upgrades/downgrades with proration, apply coupons and discounts, Read article
System Design
Low-Level Design: Ride-Sharing Driver App (State Machine, Earnings, Location)
7 min read Low-Level Design: Ride-Sharing Driver App The driver-side of a ride-sharing app manages driver state, trip offers, earnings tracking, and location Read article
System Design
Low-Level Design: Payment Processing System (Idempotency, Auth-Capture, Refunds)
6 min read Low-Level Design: Payment Processing System A payment processing system handles payment initiation, authorization, capture, refund, and failure recovery. Correctness and Read article
System Design
Low-Level Design: Social Media Feed (Follow, Post, Fan-out, Likes)
7 min read Low-Level Design: Social Media Feed (Twitter/Instagram) A social media feed system manages posts, follows, likes, and generates a personalized home Read article
System Design
Low-Level Design: Customer Support Ticketing System (SLA, Routing, State Machine)
7 min read Low-Level Design: Customer Support Ticketing System A ticketing system manages customer support requests from creation through resolution. It involves ticket Read article
System Design
Low-Level Design: Inventory Management System (Stock Tracking, Reservations)
6 min read Low-Level Design: Inventory Management System An Inventory Management System (IMS) tracks product stock levels, warehouse locations, reorder triggers, and stock Read article
System Design
Low-Level Design: Shopping Cart and Checkout (Inventory, Coupons, Payments)
6 min read Low-Level Design: Shopping Cart and Checkout System A shopping cart system manages item selection, inventory reservation, coupon application, pricing, and Read article
System Design
Low-Level Design: Hotel Reservation System (Availability, Pricing, Concurrency)
7 min read Low-Level Design: Hotel Reservation System A hotel reservation system manages room inventory, bookings, availability checks, pricing, and cancellations. It is Read article
System Design
System Design: Content Delivery Network (CDN) — Cache, Routing, Edge
5 min read System Design: Content Delivery Network (CDN) A CDN is a geographically distributed network of edge servers that caches and serves Read article
System Design
System Design: Sharding and Data Partitioning Explained
5 min read Sharding and Data Partitioning: System Design Deep Dive Sharding (horizontal partitioning) splits a large dataset across multiple database nodes so Read article