Backend Event Sourcing

Purpose

Store state changes as an append-only sequence of events. Current state is derived by replaying events. Every event is immutable, auditable, and replayable.

Agent Protocol

Trigger

Exact user phrases: "event sourcing", "event store", "event stream", "event sourced", "rehydrate from events", "event replay", "projection rebuild", "append-only log", "event history", "event store pattern".

Input Context

• Domain aggregates and their state changes.
• Event store technology (PostgreSQL, EventStoreDB, DynamoDB).
• Projection requirements (read models, search indexes, materialized views).

Output Artifact

Event sourcing design as text. No file unless requested.