What is the Action-Domain-Responder (ADR) pattern, and how does it solve Fat Controllers?

Short answer

It replaces MVC with three parts: Action (single-purpose controller), Domain (business logic and models), and Responder (response and JSON formatting).

Explanation

In large Laravel applications, controller classes such as UserController can grow to thousands of lines (Fat Controllers). ADR proposes replacing them with small, focused Action Classes that implement __invoke, such as RegisterUserAction or ExportInvoicesAction. This isolates logic, simplifies unit testing, and prevents responsibilities from overlapping.

Code example

// App/Actions/CreateOrderAction.php
class CreateOrderAction {
    public function __invoke(User $user, array $items): Order {
        // Pure business logic, isolated and independently testable
    }
}

Common mistakes

• Moving all bloated logic into generic Services that turn into bloated God Objects themselves.

Follow-up questions

• How do you write integrated Laravel Feature tests for API endpoints and validate JSON responses?

Sources

• Laravel docs — Single Action Controllers