Orchestration vs Choreography

Two fundamental patterns for coordinating distributed workflows.

Orchestration

A central coordinator (saga/PM) explicitly controls the workflow:

┌─────────────┐
│ Orchestrator│
│   (Saga)    │
└──────┬──────┘
       │
       ├──────► Aggregate A
       │
       ├──────► Aggregate B
       │
       └──────► Aggregate C

Characteristics:

• Central control point
• Explicit workflow definition
• Easier to understand/debug
• Single point of failure

In Angzarr: Sagas and Process Managers implement orchestration.

Choreography

Components react independently to events:

Aggregate A ──event──► Aggregate B ──event──► Aggregate C
                              │
                              └──event──► Aggregate D

Characteristics:

• Decentralized control
• Loose coupling
• Harder to trace workflows
• More resilient

In Angzarr: Multiple sagas can create choreographed behavior by each reacting to different events.

When to Use Each

Scenario	Pattern
Complex multi-step workflow	Orchestration (PM)
Simple domain translation	Orchestration (Saga)
Independent reactions	Choreography
Need central monitoring	Orchestration
Maximum decoupling	Choreography

Hybrid Approach

Angzarr supports combining both:

• Sagas for explicit domain translation
• Multiple sagas reacting to same events (choreography)
• Process managers for complex orchestration