- API design & implementation
REST or GraphQL endpoints with documentation (Swagger / Postman collection).
- Database design & setup
Normalized schema, indexing, and migrations (PostgreSQL, MySQL, MongoDB, etc.).
- Authentication & authorization system
JWT, OAuth, or session-based, with role-based access control.
- Business logic & core functionality
Implemented according to product requirements (payments, notifications, analytics, etc.).
- Background jobs & queue system
(BullMQ, RabbitMQ, or AWS SQS for async processing).
- Server configuration / DevOps setup
Docker, CI/CD pipeline, environment variables, secrets management.