Decompose by Subdomain (DDD)

Use Domain-Driven Design bounded contexts to create services with their own language and model.

DDD

Detailed Description

A bounded context defines where a model and vocabulary are valid. In microservices, that boundary often becomes a service boundary.

This avoids one giant shared model that means different things to different teams.

Core domain -> OrderService
Supporting -> InventoryService
Generic -> AuthService
Each context owns its model

Pros

Clear models, bounded contexts, rich domain language

Cons

Requires domain modeling maturity

Examples: DDD by Eric Evans, Vaughn Vernon