Serializing for an API

[
    'title' => 'Profile Onboarding',
    'percentage' => 50.0,
    'next_step' => [
        'key' => 'upload-photo',
        'title' => 'Upload Photo',
        'cta' => 'Upload Now',
        'action' => 'users@photo@upload',
        'is_completed' => false,
        'is_optional' => false,
        'meta' => [],
        'group' => null,
    ],
    'current_step' => [
        // same shape as next_step
    ],
    'is_completed' => false,
    'steps' => [
        // each step as ['key', 'title', 'cta', 'action', 'is_completed', 'is_optional', 'meta', 'group']
    ],
]

use RoundlyConsulting\Onboarding\DataTransferObjects\FlowData;

$data = Onboarding::for($user)?->toData();   // ?FlowData

$data?->title;          // ?string
$data?->percentage;     // float
$data?->currentStep;    // ?StepData — the same step as $data->nextStep
$data?->steps;          // list<StepData>
$data?->isCompleted;    // bool

$data?->currentStep?->key;      // 'upload-photo'
$data?->currentStep?->title;    // resolved title

use Illuminate\Http\Request;
use Illuminate\Support\Facades\Route;
use RoundlyConsulting\Onboarding\Facades\Onboarding;

Route::middleware('auth')->get('/api/onboarding', function (Request $request) {
    return response()->json(Onboarding::for($request->user())?->toData());
});