System Design Interview: Real-Time Analytics Dashboard (ClickHouse / Druid)
7 min read What Is Real-Time Analytics? Real-time analytics provides insights on data that is seconds to minutes old — not the hours […] Read article
System Design
System Design
System Design Interview: Live Location Tracking (Uber / Lyft Driver GPS)
7 min read Overview Live location tracking ingests continuous GPS updates from millions of mobile devices and serves current location data to nearby Read article
System Design
System Design Interview: E-commerce and Inventory Management System
6 min read Core Components An e-commerce system handles product catalog, inventory tracking, shopping cart, order placement, payment processing, and fulfillment. Shopify processes Read article
Algorithms
Divide and Conquer Interview Patterns: Merge Sort, Quick Select, Master Theorem
7 min read The Divide and Conquer Paradigm Divide and conquer solves problems by: (1) Divide — split the problem into smaller subproblems Read article
Algorithms
Binary Tree Interview Patterns: Traversal, DFS, BFS, and Classic Problems
7 min read Tree Traversal Fundamentals Binary tree problems appear in nearly every technical interview. The foundation is traversal order, which determines which Read article
System Design
System Design Interview: Real-Time Chat System (WhatsApp / Slack)
7 min read Core Requirements A real-time chat system must: deliver messages in under 100ms end-to-end, support 1:1 and group chats, handle offline Read article
System Design
System Design Interview: Ride-Sharing Dispatch System (Uber/Lyft)
6 min read Dispatch System Requirements A ride-sharing dispatch system matches riders with nearby available drivers in real time. Core requirements: find available Read article
System Design
System Design Interview: WebRTC and Real-Time Video Architecture
12 min read WebRTC Architecture Overview WebRTC (Web Real-Time Communication) is an open standard that enables peer-to-peer audio and video in browsers and Read article
Algorithms
Dynamic Programming Patterns: Tree DP, Digit DP, and Bitmask DP
13 min read TL;DR — Tree DP, digit DP, and bitmask DP are three dynamic programming patterns, each matched to a different problem shape: Read article
System Design
System Design Interview: Financial Exchange and Matching Engine
11 min read Exchange Architecture Overview A financial exchange matches buy and sell orders — a buyer willing to pay $100 for AAPL Read article
System Design
System Design Interview: Social Graph and Friend Recommendations
13 min read Social Graph Requirements A social graph stores relationships between users (friendships, follows, connections) and enables graph queries: friends of friends, Read article
System Design
System Design Interview: Notification System at Scale
12 min read Notification System Requirements A notification system routes messages from producers (application events) to consumers (users) via multiple channels: push notifications Read article
System Design
System Design Interview: Job Scheduler and Task Queue
12 min read Why Task Queues? Task queues decouple work production from work execution. Instead of processing a long-running task synchronously (blocking the Read article
System Design
System Design Interview: Database Indexing and Query Optimization
13 min read Why Indexing Matters Without an index, a SELECT with a WHERE clause requires a sequential scan — reading every row Read article
System Design
System Design Interview: Real-Time Collaborative Editing (Google Docs)
14 min read TL;DR — Design it around a concurrency-control algorithm — Operational Transformation (OT) or Conflict-free Replicated Data Types (CRDTs) — that lets Read article
