Outbox Pattern

Kind: pattern

Layer: Execution Core

Aliases: Transactional Outbox

Record: architecture:outbox-pattern

Severity: recommended

Scope: persistence, messaging

Canonical: Ontology

A design pattern that writes an outgoing message in the same local transaction as the state change, and a relay publishes it afterwards.

Listed in Architecture principles, after Saga Pattern and before Compensating Transaction.

Requires

• Local Transaction
• Message Relay

Reinforces

• Event Reliability

Enables

• Atomic State Change + Message Publish

Conflicts with

• Dual Write

In tension with

• Relay Complexity

Tensions

• Outbox Pattern / Relay Complexity

Violated by

• Dual Write

Refactored by

• Message Relay

Severity

• recommended

Category

• Event / Messaging / Asynchronous Architecture

Refactors

• Distributed Monolith
• Event-Driven Architecture

Linked from

• Anti-patterns
• Event / Messaging / Asynchronous Architecture
• Event Messaging Async
• Severity levels
• The resolutions