API resources replaced the transformer package

Shaping a model for JSON has meant a transformer library or toArray() on the model, and the second couples the wire format to the database columns — so adding a column changes the API.

class OrderResource extends JsonResource
{
    public function toArray($request)
    {
        return [
            'id'       => $this->reference,        // not the primary key
            'total'    => $this->total_cents,
            'currency' => $this->currency,
            'lines'    => OrderLineResource::collection($this->whenLoaded('lines')),
        ];
    }
}

whenLoaded() is the detail worth adopting immediately: it includes the relation only if it was eager loaded, so a resource cannot cause an N+1 by being rendered somewhere that did not load it. Exposing reference rather than the primary key is the other habit — an auto-increment id in a public API leaks volume and invites enumeration.