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.
5 min read What Is a Config Management Service? A configuration management service stores application settings that need to change without a code […] Read article
6 min read The Core Challenge A flash sale sells a limited quantity (e.g., 1000 units) at a discounted price for a short Read article
6 min read What Is a Geo-Proximity Service? A geo-proximity service finds entities (businesses, drivers, users) near a given location. Core operations: store Read article
5 min read Core Entities Provider: provider_id, name, timezone, working_hours (JSONB: {“MON”: [“09:00″,”17:00”], …}), slot_duration_minutes (e.g., 30). Appointment: appointment_id, provider_id, client_id, start_time (UTC), Read article
6 min read Core Entities Content: content_id, type (TEXT, IMAGE, VIDEO), author_id, platform, raw_content / storage_url, created_at. ModerationDecision: decision_id, content_id, verdict (APPROVED, REMOVED, Read article
6 min read What Is Event-Driven Architecture? Event-Driven Architecture (EDA) decouples services by having them communicate through events rather than direct API calls. Read article
5 min read Core Entities Driver: driver_id, current_location (lat/lng), status (AVAILABLE, ON_TRIP, OFFLINE), vehicle_type, rating. Rider: rider_id, payment_method_id, rating. Trip: trip_id, rider_id, driver_id, Read article
7 min read The Video Upload and Processing Problem YouTube processes 500 hours of video every minute. Each uploaded video must be transcoded Read article
7 min read Requirements Functional: send notifications via multiple channels (push, email, SMS, in-app), support notification templates with variable substitution, allow users to Read article
7 min read Requirements Functional: place orders (cart checkout → payment → fulfillment), track order status through lifecycle, handle partial fulfillment (items shipped Read article
7 min read Requirements Functional: record expenses with amount, category, date, and notes; support multiple currencies with conversion; tag and categorize expenses; view Read article
7 min read Requirements Functional: 1-on-1 and group messaging, real-time message delivery, message persistence and history, read receipts (sent/delivered/read), user presence (online/offline/last seen), Read article
8 min read Requirements Functional: search available rooms by date range and city, view room details and pricing, book a room (atomic reservation), Read article
6 min read Requirements Functional: create coupons (percent off, fixed amount, free shipping), set constraints (minimum order, expiry, usage limits, specific products/categories, single Read article
6 min read The Problem: Counting at Scale Incrementing a counter sounds trivial — until you need to count 10 million page views Read article
