Learn System Design
System design, the way real interviews test it
Pick a level, then learn every concept the same way: read it, then write your own design answer and self-compare against a model answer. No code to run, just the reasoning that wins rounds.
Level 0: Interview & Communication Method
Run a system-design round like a senior: scope, estimate, structure the walkthrough, and drive tradeoffs.
15 lessons · ~6h
Level 1: Foundations & Mental Models
The networking, API-contract, and performance fundamentals every later design assumes.
21 lessons · ~9h
Level 2: Data Storage & Modeling
Relational vs NoSQL, storage engines, indexing, and modeling for access patterns.
17 lessons · ~8h
Level 3: Scaling the Data Tier
Replication, sharding, caching, CDN/search, and keeping derived data in sync at scale.
16 lessons · ~8h
Level 4: Scaling Compute & Traffic
Stateless scale-out, load balancing, gateways, rate limiting, autoscaling, and overload protection.
14 lessons · ~7h
Level 5: Distributed Systems Core
CAP/PACELC, consistency, clocks, consensus, distributed transactions, and failure handling.
18 lessons · ~9h
Level 6: Asynchronous & Event-Driven Systems
Messaging models, Kafka and the log, delivery guarantees, stream processing, and schema governance.
15 lessons · ~7h
Level 7: Reliability, Resilience & Operations
SLOs and error budgets, observability, resilience patterns, redundancy and multi-region DR, and safe deploys and chaos.
17 lessons · ~8h
Level 8: Security, Privacy & Multi-tenancy
Authentication and identity, authorization and tenancy, encryption and secrets, abuse and perimeter defense, and privacy, compliance, and audit.
16 lessons · ~8h
Level 9: Modern Architecture & Delivery
Service architecture, containers and orchestration, serverless and edge, delivery and FinOps, and data-intensive analytics.
16 lessons · ~8h
Level 10: Applied Case Studies
The full-length 'design X' interviews: foundational building blocks, social and feed, geo and media, storage and infra systems, and commerce, money, and analytics.
28 lessons · ~16h
Level 11: Specialized & Frontier Systems
The frontier: ML systems, LLM and GenAI infrastructure, real-time analytics and globally consistent data, and IoT, edge, and time-series.
15 lessons · ~8h