Learn to design scalable, reliable systems that handle millions of users. System design interviews test your ability to architect real-world applications, considering tradeoffs, scalability, and best practices.
Core Topics:
Scalability: Load balancing, horizontal vs vertical scaling
Storage: Databases (SQL vs NoSQL), caching (Redis, Memcached)
Reliability: Replication, failover, disaster recovery
Performance: CDNs, caching strategies, database indexing
Common Design Questions:
Design URL shortener (bit.ly)
Design rate limiter
Design Twitter/Instagram feed
Design messaging system (WhatsApp)
Design file storage (Dropbox)
Interview Level: Senior engineers (L5+) at FAANG companies. Requires 3-5+ years experience to tackle effectively.
Preparation: Study system design patterns, understand distributed systems fundamentals, and practice mock interviews.
Overview A file upload system must handle large binary transfers reliably — resuming interrupted uploads, scanning for malware, validating content […]
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Overview A digest email system aggregates user-relevant events over a configurable time window and delivers a single summarized email rather
Overview A price history system records product price changes over time, enables historical chart queries, and fires alerts when a
Overview A token bucket rate limiter controls how many requests a client can make within a time period while allowing
Distributed Tracing System: Low-Level Design A distributed tracing system records the journey of a request as it propagates through multiple
Multi-Region Failover System: Low-Level Design A multi-region failover system routes traffic away from a failing region to a healthy standby,
Tenant Isolation System: Low-Level Design A multi-tenant SaaS application serves many organizations (tenants) from a shared infrastructure. Tenant isolation ensures
Saga Orchestration System: Low-Level Design A saga is a sequence of local transactions, each in a separate service, that together
SLA Monitoring System: Low-Level Design An SLA monitoring system tracks whether a service is meeting its availability, latency, and error
Canary Deployment System: Low-Level Design A canary deployment system routes a small fraction of production traffic to a new version
Webhook Subscription System: Low-Level Design A webhook subscription system lets external developers register URLs to receive event notifications. Unlike the
Payment Refund System: Low-Level Design A payment refund system reverses a completed charge — partially or fully — and ensures
Activity Feed Aggregator: Low-Level Design An activity feed aggregator collects events from multiple services — post created, user followed, payment
