A full-stack technical challenge: bulk-register clients from a CSV upload and distribute them across operators — with CSV import/export and a per-layer tested NestJS API. TypeScript end to end.
Solution to a full-stack technical challenge. The app lets you view operators and the clients assigned to them, register clients in bulk by uploading a CSV (each client is distributed to an operator on upload), and export all clients back to CSV.
- View operators and their assigned clients.
- Upload a CSV to register clients immediately, distributed across operators (round-robin).
- Export all clients to a CSV file.
- Redistribute existing clients across operators.
| Layer | Technology |
|---|---|
| Frontend | TypeScript, React, Next.js, React Query, React Hook Form, Zod, Tailwind, shadcn/ui |
| Backend | NestJS, Multer, csv-parser, fast-csv |
| ORM / DB | Prisma · MySQL |
| Testing | Jest |
| Runtime | Docker / Docker Compose |
Database schema:
A NestJS API with clear layering — controllers → services → repositories, with DTOs,
entities, and validators per module (clients, operators) — behind a Next.js frontend.
CSV parsing is streamed; client distribution is a round-robin over the available operators.
Unit tests with Jest, one spec per layer (service, controller, validator):
cd backend && yarn testPrerequisites: Docker + Docker Compose V2.
The .env.example ships pre-filled (this is not a production app) — just copy it to .env.
docker compose up --build -dOperators — POST /operators, GET /operators, GET /operators/:id,
PATCH /operators/:id, DELETE /operators/:id.
Clients — GET /clients, GET /clients/:id, POST /clients, PATCH /clients/:id,
DELETE /clients/:id, POST /clients/upload (CSV, form-data file),
GET /clients/download (CSV export), GET /clients/redistribute.
João Barbosa — Software Engineer (backend / platform). LinkedIn · GitHub