Route (backend/src/api/routes/)     → DI setup + routing
Controller (backend/src/api/controllers/) → Zod validation + ApiResponse
Service (backend/src/services/)     → Business logic
Repository (backend/src/repositories/) → Database queries

import { Router } from 'express';
const router = Router();

// Manual DI
const repo = new MyRepository();
const service = new MyService(repo);
const controller = new MyController(service);

router.get('/', (req, res, next) => controller.getAll(req, res, next));
router.post('/', (req, res, next) => controller.create(req, res, next));

export default router;

const CreateSchema = z.object({
  name: z.string().min(1).max(255),
});

export class MyController {
  constructor(private service: MyService) {}

  async create(req: Request, res: Response, next: NextFunction) {
    try {
      const data = CreateSchema.parse(req.body);
      const result = await this.service.create(data);
      res.json({ success: true, data: result } as ApiResponse<typeof result>);
    } catch (error) {
      next(error);
    }
  }
}

import myRouter from './api/routes/my';
app.use('/api/my-resource', myRouter);

// Success
{ success: true, data: { ... } }

// Error (via errorHandler middleware)
{ success: false, error: { message: "...", code: "ERROR_CODE" } }