architecture

To decide where to put new Rails logic, identify its primary responsibility: use models for persistence, service objects for orchestration, query objects for read-heavy logic, and presenters for display formatting.

The best way to refactor a fat Rails controller is extracting multi-model orchestration into service objects and moving read-heavy retrieval logic into query objects, enforcing single-responsibility per file.

Rails service objects and query objects interact through one-way calls and explicit layer boundaries. Services orchestrate business logic by calling queries for data retrieval, preventing reverse dependencies and reducing coupling.

Extract a Rails presenter when you need to isolate display formatting logic from models and controllers. This enforces single-responsibility per file and keeps persistence logic separated from view concerns.

Yes, this architecture guidance handles multi-model orchestration by directing cross-cutting feature logic into service objects. Controllers coordinate requests while services manage the underlying multi-model interactions.

Tight coupling in Rails happens without clear layer interaction rules. Applying explicit layer boundaries and one-way call directives between models, services, queries, and presenters reduces dependencies and improves testability.