System Design

Practical prep for system design interviews — frameworks, estimation, and real design walkthroughs.

Foundation guide

System Design Interview Complete Guide

Build the fundamentals: estimation, scaling, storage, caching, messaging, reliability, and interview structure.

Complete reference · Start here Explore the guide
Design walkthrough

Design Twitter

Design a production-scale home timeline and reason through fan-out, celebrity accounts, caching, Kafka, and failures.

Feeds · Hybrid fan-out · Senior-level Read the walkthrough
Design walkthrough

Design a URL Shortener

Design a high-read short-link service and reason through unique codes, redirects, caching, analytics, and viral hot keys.

Redirects · Base62 · Senior-level Read the walkthrough
Design walkthrough

Design a Food Delivery Tracking System

Design Zomato-style live tracking: order states, rider GPS, WebSockets, geo matching, and what to do when updates drop.

Real-time · Location · Senior-level Read the walkthrough
Design walkthrough

Design a Tiered Messaging Platform

Design a billion-message SMS, email, and push platform where bulk campaigns cannot starve critical traffic.

Priority tiers · Providers · Senior-level Read the walkthrough
Design walkthrough

Design a Customer-Facing Search System

Design hotel search from query understanding to retrieval, ranking, live price enrichment, and resilient indexing.

Search · Ranking · Senior-level Read the walkthrough
Design walkthrough

Design a Distributed Cache

Design an in-memory cache with partitioning, replicas, eviction, hot-key protection, and safe failure recovery.

Caching · Consistent hashing · Senior-level Read the walkthrough
Design walkthrough

Design a Booking System

Design count-based reservations with atomic holds, payment recovery, idempotency, and no double booking.

Inventory · Payments · Senior-level Read the walkthrough
Design walkthrough

Design an Employee Management System

Design an employee directory with hierarchy, optimistic locking, cache, search, audit, and RBAC.

Org graph · Outbox · Senior-level Read the walkthrough
Design walkthrough

Design a Ticket Management System

Design a Jira-like tracker with issue keys, configurable workflows, optimistic locking, search, and notifications.

Workflows · Outbox · Senior-level Read the walkthrough
Design walkthrough

Design an Invoice Generation System

Design immutable invoices with async PDFs, object storage, outbox events, and idempotent workers.

Snapshots · Outbox · Senior-level Read the walkthrough
Design walkthrough

Design WhatsApp

Design 1:1 and group chat with sequences, multi-device WebSockets, offline catch-up, and hybrid fan-out.

Chat · Ordering · Senior-level Read the walkthrough
Design walkthrough

Design YouTube

Design video upload, transcoding, CDN playback, sharded view counts, search, and a ranked home feed.

Streaming · CDN · Senior-level Read the walkthrough
Design walkthrough

Design Uber

Design ride matching with Redis GEO, atomic driver reservation, offer timeouts, and idempotent payment.

Dispatch · GEO · Senior-level Read the walkthrough