description: "Symfony API response standardization — JSON payload format, exception handling, controllers, REST endpoints, error responses, debug mode. Triggers on: API, endpoint, controller, response, error handling, JSON, REST, API response, exception subscriber, HTTP"

Symfony API Response Standard

You are an expert in building standardized REST APIs within Symfony hexagonal architecture.

When to Activate

• User creates API endpoints or controllers
• User asks about response format or error handling
• User needs exception handling for APIs
• User mentions REST, JSON, or API design

Standard JSON Payload

ALL API responses use this format:

{
    "result": null,
    "error": null,
    "extra": null,
    "status": 200
}

Success Response

{
    "result": {"id": "uuid-123", "name": "John"},
    "error": null,
    "extra": null,
    "status": 200
}

Error Response

{
    "result": null,
    "error": {"code": "USER_NOT_FOUND", "message": "User not found"},
    "extra": null,
    "status": 404
}

Debug Mode (APP_DEBUG=true)

{
    "result": null,
    "error": {"code": "INTERNAL_ERROR", "message": "Something went wrong"},
    "extra": {"debug": {"exception": "...", "trace": "..."}},
    "status": 500
}

Controller Pattern

Controllers are thin — dispatch to buses only:

namespace App\Presentation\{Module}\API;

use App\Presentation\Shared\ApiResponseTrait;
use Symfony\Component\Routing\Attribute\Route;
use Symfony\Component\Security\Http\Attribute\IsGranted;

#[Route('/api/{module}')]
final class {Entity}Controller
{
    use ApiResponseTrait;

    public function __construct(
        private readonly MessageBusInterface $commandBus,
        private readonly MessageBusInterface $queryBus,
    ) {
    }

    #[Route('', methods: ['POST'])]
    #[IsGranted('ROLE_...')] // ALWAYS include
    public function create(Request $request): JsonResponse
    {
        // 1. Parse input
        // 2. Create command
        // 3. Dispatch to command bus
        // 4. Return success response
    }
}

References

See references/ for detailed guides:

• payload-schema.md — ApiResponseTrait, response helpers
• exception-handling.md — ExceptionSubscriber, error mapping