Uncategorized

Introduction Real-time analytics surfaces business metrics such as DAU, revenue, and conversion rates with sub-second query latency on continuously updating […]

Introduction Metrics collection is the foundation of system observability. The four core metric types cover most monitoring needs: a counter

Introduction Polling systems must ensure one vote per eligible voter, prevent fraud, aggregate results in real time, and optionally preserve

Introduction Electronic Health Record systems store and exchange patient health data across providers, payers, and patients. Design must prioritize data

A trading engine matches buy and sell orders for financial instruments. Correctness and latency are paramount — microsecond-level matching with

IoT platforms ingest telemetry from millions of devices with high write throughput, store time-series data efficiently, and enable real-time alerting

Multiplayer game servers synchronize game state across all players in a session with minimal latency. The design must handle packet

Introduction Logistics tracking systems process millions of scan events daily, maintain accurate package state, and surface real-time location to customers.

ATM networks process card transactions across millions of terminals through authorization switches. The design must be highly available, idempotent, and

Airport management systems orchestrate hundreds of daily flight operations including gate assignment, ground handling, baggage routing, and passenger information display.

Introduction Collaborative editors in the style of Google Docs allow multiple users to edit the same document simultaneously with real-time

Introduction KYC (Know Your Customer) requires verifying user identity using government-issued documents. It is a regulatory requirement for fintech companies,

Introduction Live streaming requires low-latency ingest, real-time transcoding to multiple bitrates, and global CDN distribution to millions of concurrent viewers.

An ad serving system delivers targeted advertisements to users in real time, managing the full lifecycle from auction to billing.

Drone delivery is one of the more mechanically complex LLD problems: you have a physical object moving through three-dimensional space,