projection-patterns

Guide building projections and read models for event-sourced architectures.

Updated Jul 8, 2026
One-click install
npx skills add https://github.com/PriyanshKuniyal/gemini-cli-resources --skill projection-patterns-priyanshkuniyal
Or copy as Structured Prompt for Agent
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Skill: projection-patterns
Source: https://github.com/PriyanshKuniyal/gemini-cli-resources/tree/main/extensions/claude-code-workflows/plugins/backend-development/skills/projection-patterns
Command: npx skills add https://github.com/PriyanshKuniyal/gemini-cli-resources --skill projection-patterns-priyanshkuniyal

SYSTEM DOCUMENTATION & REQUIREMENTS

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

What problem does it solve?

This Skill provides guidance and tools for building projections in event-sourced systems, addressing the challenge of optimizing query performance and managing read models efficiently.

Core Features & Use Cases

  • Projection Architecture: Understand and implement different types of projections (Live, Catchup, Persistent, Inline) to manage data consistency and performance.
  • Projection Templates: Offers templates for creating basic and advanced projections, including examples for different use cases.
  • Best Practices: Provides dos and don'ts for building robust projections that are idempotent, transactional, and checkpointed.

Quick Start

Run the skill to get an overview of projection patterns and best practices.

Frequently Asked Questions about projection-patterns

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

FAQPage Schema
How do I build projections for event-sourced systems?

To build projections for event-sourced systems, implement different projection types like Live, Catchup, Persistent, and Inline to manage data consistency. You create materialized views and CQRS read models to optimize query performance.

What are the different types of projections in CQRS architectures?

The main projection types in CQRS architectures are Live, Catchup, Persistent, and Inline projections. These patterns help manage data consistency and query performance across your event-sourced read models.

How do I optimize query performance for event sourcing read models?

Optimize query performance for event sourcing read models by creating materialized views and applying projection patterns. Using idempotent, transactional, and checkpointed projections ensures robust and efficient data retrieval.

What are the best practices for creating idempotent projections?

Best practices for creating idempotent projections include ensuring your projections are transactional and checkpointed. Following these dos and don'ts guarantees robust projections that manage data consistency efficiently.

Do I need to understand event sourcing principles to implement projection patterns?

Yes, you need a solid understanding of event sourcing principles and basic knowledge of data modeling to implement projection patterns. This foundation is required to effectively build CQRS read sides and materialized views.

What is the best way to manage data consistency in event-sourced projections?

The best way to manage data consistency in event-sourced projections is by selecting the appropriate projection architecture, such as Catchup or Persistent projections. Applying transactional and checkpointed best practices ensures reliability.