projection-patterns

Design and implement projections and read models for event-sourced systems.

Updated May 30, 2026

Search Tags:#CQRS #read models #event sourcing #projections #event streams

Ready to run

npx skills add https://github.com/sandeshbagmare/AgenticQ --skill projection-patterns-sandeshbagmare

💬 Prompt for ChatGPT / Claude Chat▼

Please help me install this Agent Skill.
Skill: projection-patterns
Source: https://github.com/sandeshbagmare/AgenticQ/tree/main/examples/python_agenticq_demo/.claude/plugins/backend-development/skills/projection-patterns
Command: npx skills add https://github.com/sandeshbagmare/AgenticQ --skill projection-patterns-sandeshbagmare

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes scripts (resource) and references (resource) components.

What problem does it solve?

This Skill provides a guide to building projections and read models from event streams, which is essential for optimizing query performance and managing complex event-sourced systems.

Core Features & Use Cases

Build Read Models: Create materialized views for efficient data access.
Projection Types: Offers live, catchup, persistent, and inline projections.
Best Practices: Provides guidelines for designing projections and handling events.
Use Case: Ideal for implementing CQRS read sides, materialized views, and real-time dashboards in event-sourced applications.

Quick Start

Implement a live projection for real-time state queries using the provided templates and examples.

Frequently Asked Questions about projection-patterns

High-intent search queries and answers about installing and using this skill.

FAQPage Schema

How do I build read models from event streams in a CQRS architecture?▼

Projections in event sourcing process event streams to build and update read models, creating materialized views that allow efficient data access without reconstructing aggregate state from the full event history.

What are the different types of projections for event-sourced systems?▼

The projection types detailed for event-sourced systems include live, catchup, persistent, and inline projections, each managing event stream consumption differently to build read models.

How do I optimize query performance for real-time dashboards in event-sourced applications?▼

You optimize query performance in event-sourced applications by implementing live projections to create materialized views, enabling rapid data retrieval for real-time dashboards.

Do I need prior knowledge of event sourcing and CQRS to implement projections?▼

Yes, implementing projections requires prerequisite knowledge of event sourcing and CQRS patterns, as this guidance focuses on managing event streams and building the CQRS read side.

When should I use catchup projections versus persistent projections?▼

Catchup projections process historical event streams to build read models from scratch, while persistent projections maintain ongoing event stream state, with best practices dictating selection based on your query requirements.

What is the best way to handle events when designing CQRS read side projections?▼

The best way to handle events when designing CQRS read side projections is to follow established projection design best practices, ensuring accurate materialized views and efficient event stream processing.