CQRS
Separates read and write operations into different models. Commands handle writes, queries handle reads — often with different data stores optimized for each purpose.
CQRS: Separate Commands from Queries
Using different models for writes and reads so each can be optimized independently.
CQRS in Production: Projections and Read Models
Building projections, managing lag, and scaling reads independently.
Advanced CQRS: Event Sourcing and Sagas
Event-sourced write models, saga orchestration, and consistency management.
CQRS: Review & Mastery Quiz
Scenario questions on split models, projections, and event sourcing.
Free Books & Guides
Refactoring.Guru — CQRS
The definitive modern guide to the CQRS pattern. Clear explanations, UML diagrams, real-world analogies, and code examples in multiple languages.
SourceMaking — CQRS
A comprehensive companion guide covering the CQRS pattern with detailed rules of thumb, criticisms, and robust code snippets.
GoF Design Patterns — CQRS
The original Gang of Four book describing the pattern. Available in the "Design Patterns: Elements of Reusable Object-Oriented Software" on Wikipedia.
Official Documentation
Video Courses
freeCodeCamp — Design Patterns Course
A comprehensive multi-hour video course covering all major design patterns with implementations in JavaScript and TypeScript.
Design Patterns in Modern JavaScript Playlist
YouTube playlist covering creational, structural, and behavioral patterns with clear code walkthroughs.
Web Dev Simplified — CQRS
Clear, concise video tutorials covering design patterns with practical examples.
Practice & Examples
Awesome Low-Level Design (GitHub)
A curated collection of free LLD resources, pattern implementations, and interview problems across multiple languages.
Design Patterns Implementation (GitHub)
The most popular open-source collection of design pattern implementations with detailed explanations.
Refactoring.Guru Examples in CQRS
Code examples of the CQRS pattern in TypeScript, Python, Java, and more.