Event-Driven Architecture

Patterns for building reactive, decoupled Python applications using domain events and commands.

Foundation

These patterns build on domain-driven architecture principles (see domain-driven-architecture skill for Repository, Service Layer, Unit of Work, and Aggregates).

Core Patterns

Domain Events

Facts about what happened in the business domain.

• Immutable dataclasses with past-tense naming (OrderAllocated, OutOfStock)
• Aggregates collect events during operations
• Published after transaction commits

Commands

Instructions to perform actions - requests that may fail.