projection-patterns

What problem does it solve?

Projection patterns provide a disciplined approach to turning event streams into queryable read models, enabling scalable CQRS read sides and materialized views.

Core Features & Use Cases

• Live projections: maintain real-time read models from active event streams.
• Catchup projections: rebuild read models from historical events.
• Persistent projections: checkpoint state to allow resuming after failures.
• Inline projections: ensure strong consistency by updating read models in the same transaction as writes.
• Templates and patterns: ready-to-adapt projectors for common domain scenarios (e.g., order processing, product catalogs, customer analytics).

Use cases include building order read models, dashboards, search indexes, and cross-stream analytics in event-sourced architectures.

Quick Start

Define a Projection subclass, wire it to a Projector, register it, and start processing events.