System Design Guide

1. Fundamentals

Topic	Link	Learning Objective	Exercise
Scalability	Link	Understand horizontal vs vertical scaling and when to apply each.	Identify a service in our system that needs to scale and propose a strategy.
Latency vs Throughput	Link	Learn the difference and how to measure them.	Benchmark an API endpoint using `wrk` or `ab`.
CAP Theorem	Link	Understand the tradeoff between Consistency, Availability, and Partition Tolerance.	Classify which part of CAP applies to PostgreSQL and MongoDB.
ACID Transactions	Link	Learn how databases ensure transaction integrity.	Write a sample ACID transaction in PostgreSQL.

2. Consistency & Reliability

Topic	Link	Learning Objective	Exercise
Strong vs Eventual Consistency	Link	Learn how data consistency behaves in distributed systems.	Describe how eventual consistency applies to our replication setup.
Fault Tolerance	Link	Learn strategies to maintain service availability during failures.	Design a failover plan for one backend service.
Disaster Recovery	Link	Understand DR concepts like RTO and RPO.	Write a short DR plan for our system.
Data Replication & Redundancy	Replication / Redundancy	Differentiate between replication and redundancy.	Draw how replication works in our databases.

3. Communication Between Services

Topic	Link	Learning Objective	Exercise
Synchronous vs Asynchronous	Link	Compare synchronous and asynchronous messaging.	Design an async version of an existing sync API.
REST vs RPC	Link	Learn when to use REST vs RPC.	Write a REST and RPC version of the same endpoint.
API Design	Link	Understand REST best practices and versioning.	Design an API and document it using OpenAPI.
API Gateway & Rate Limiting	Gateway / Rate Limit	Protect services and manage traffic effectively.	Implement a rate limiter using Redis.

4. Data & Storage

Topic	Link	Learning Objective	Exercise
SQL vs NoSQL	Link	Understand when to choose SQL or NoSQL.	Match data types to the right database type.
Database Indexes	Link	Learn query optimization with indexes.	Compare query times with and without indexes.
Database Scaling & Sharding	Scaling / Sharding	Learn how databases scale horizontally.	Draw a sharding architecture diagram.

5. Infrastructure & Distribution

Topic	Link	Learning Objective	Exercise
Load Balancing	Link	Learn load balancing algorithms and use cases.	Implement a simple load balancer using Nginx or Traefik.
Service Discovery	Link	Understand how microservices find each other.	Explain how Consul or Istio manages service discovery.
Proxy Server	Link	Understand how proxies route and cache traffic.	Analyze our system’s proxy architecture.
CDN (Content Delivery Network)	Link	Learn how CDNs reduce latency globally.	Describe how a CDN improves our user experience.

6. Distributed Systems Concepts

Topic	Link	Learning Objective	Exercise
Consistent Hashing	Link	Understand data distribution among nodes.	Simulate a consistent hashing ring.
Consensus Algorithms	Link	Learn Raft and Paxos basics.	Summarize how Raft reaches agreement.
Gossip Protocol	Link	Understand peer-to-peer communication.	Design a health-check system using gossip.
Distributed Locking	Link	Learn about concurrency control across services.	Implement Redis-based distributed locks.

7. Observability & Resilience

Topic	Link	Learning Objective	Exercise
Distributed Tracing	Link	Learn to trace requests across services.	Integrate OpenTelemetry tracing.
Heartbeat	Link	Monitor service health.	Write a simple heartbeat monitor.
Circuit Breaker	Link	Prevent cascading failures.	Use a circuit breaker library in your service.
Checksum	Link	Verify data integrity.	Implement a SHA256 checksum for a file transfer.

8. Performance & Optimization

Topic	Link	Learning Objective	Exercise
Caching & Distributed Caching	Cache / Dist Cache	Learn how caching improves speed and scalability.	Add a cache layer to one API endpoint.
Bloom Filters	Link	Understand probabilistic data structures.	Implement a simple Bloom Filter in code.
Horizontal vs Vertical Scaling	Link	Decide how to scale services effectively.	Create a scaling plan for one service.

9. Tradeoffs & Decision-Making

Topic	Link	Learning Objective	Exercise
Top 15 Tradeoffs	Link	Learn to evaluate pros and cons of system design decisions.	Analyze 3 design choices in our system and identify their tradeoffs.