System Design Guide
"Design a social feed in 45 minutes." This question separates senior engineers from everyone else. Master the 4-step frameworkused by engineers at top tech companies.
4-Step System Design Framework
Follow this proven structure in every system design interview
Requirements & Scope
Clarify functional and non-functional requirements. Ask about scale, users, and constraints.
High-Level Design
Draw the core components: clients, servers, databases, caches. Show data flow.
Deep Dive
Go deep on critical components. Discuss trade-offs and alternatives.
Scale & Edge Cases
Handle bottlenecks, failure scenarios, and edge cases.
Essential Building Blocks
Load Balancing
Distribute traffic across servers
L7/L4, Round Robin, Consistent Hashing
Database Scaling
Handle growing data needs
Sharding, Replication, Partitioning
Caching
Speed up read-heavy systems
Redis, Memcached, CDN
Message Queues
Async processing & decoupling
Kafka, RabbitMQ, SQS
CDN
Serve static content globally
CloudFlare, Fastly, Akamai
Consistency
Data consistency patterns
CAP Theorem, ACID, BASE
Common System Design Questions
Design Twitter/X
Feed, Timeline, Real-time
Design URL Shortener
Hashing, Database
Design Instagram
Media, CDN, Feed
Design WhatsApp
Messaging, Presence, E2E
Design YouTube
Video, Streaming, CDN
Design Uber
Geolocation, Matching
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