wise-receipt

byLoths Vazuri

You are a senior enterprise software architect and full-stack engineer specialized in fiscal systems, fintech integrations, and tax-compliant POS infrastructure. Build a production-grade Virtual Fiscal Device Management System (VFDMS) for Tanzania TRA integration using: Frontend: - React.js - Tailwind CSS - React Query - Redux Toolkit - Socket.IO client - Axios Backend: - Django - Django REST Framework - PostgreSQL - Redis - Celery - WebSockets using Django Channels System Goal: Create a SaaS platform that allows vendors, supermarkets, shops, restaurants, and POS providers to: - Connect POS systems - Manage fiscal devices virtually - Send transactions to TRA in real-time - Generate fiscal receipts - Store fiscal records - Track device status - Monitor receipt generation live - Support multiple branches and vendors The architecture must support: - Multi-tenant SaaS - Real-time receipt processing - API-first infrastructure - Device abstraction layer - High scalability - Offline queue synchronization - Fiscal middleware - Role-based access control Core Modules: 1. Authentication & Authorization - JWT authentication - RBAC (Admin, Vendor, Cashier, Auditor) - Multi-tenant organization system 2. Vendor Management - Register vendors - Branch management - TIN and VRN management - Fiscal profile settings 3. Virtual Fiscal Device Manager - Device registration - Device pairing - Device heartbeat monitoring - Device status tracking - Device logs - Device certificate management 4. TRA Integration Layer - TRA API connector - XML/JSON fiscal payload generator - Digital signing - Receipt verification - Error handling and retry queue - API token management - Request audit trail 5. Receipt Engine - Real-time fiscal receipt generation - QR code generation - Receipt number sequencing - Tax calculations - Receipt PDF generation - Receipt reprint system 6. POS Integration API - REST API endpoints - Webhook system - API key management - SDK-ready architecture - WebSocket events for live receipts 7. Real-Time Monitoring Dashboard - Live transactions - Device online/offline status - Revenue analytics - Tax analytics - Failed receipt monitoring - Branch comparison dashboard 8. Queue & Offline Sync Engine - Store transactions during internet outage - Automatic retry system - Sync reconciliation - Duplicate prevention 9. Audit & Compliance - Immutable audit logs - Fiscal event tracking - User activity logs - Compliance reporting 10. Notification System - SMS/email alerts - Device offline alerts - Failed TRA submission alerts Technical Requirements: - Use clean architecture - Use repository/service pattern - Use Docker - Use Nginx - Use environment variables - Implement rate limiting - Add request validation - Add centralized error handling - Add Swagger/OpenAPI docs - Add unit and integration tests - Add CI/CD workflow - Add logging and monitoring - Add API versioning - Add background workers Frontend Requirements: - Modern responsive admin dashboard - Dark/light mode - Live transaction feed - Real-time charts - Device management UI - Receipt viewer - Branch selector - Vendor analytics - Error monitoring panel Database Design: Create full PostgreSQL schema including: - users - organizations - branches - fiscal_devices - receipts - receipt_items - tax_records - transactions - audit_logs - api_keys - sync_queue - notifications Generate: 1. Full project folder structure 2. Backend architecture 3. Frontend architecture 4. PostgreSQL schema 5. API endpoint documentation 6. Django models 7. DRF serializers 8. DRF views/viewsets 9. React pages/components 10. WebSocket implementation 11. TRA integration service 12. Docker configuration 13. Deployment guide 14. Security best practices 15. Sample fiscal receipt flow 16. POS integration examples 17. Middleware architecture 18. Multi-tenant implementation 19. Celery queue setup 20. Redis caching strategy Important: - Write production-ready code - Use scalable enterprise architecture - Add comments explaining critical fiscal logic - Follow financial software security standards - Optimize for East African retail environments with unstable internet - Design system so multiple POS systems can connect simultaneously - Ensure all fiscal operations are traceable and auditable - Separate fiscal engine from POS engine using service abstraction Bonus Features: - AI anomaly detection for suspicious transactions - Inventory sync support - Mobile admin app API support - WhatsApp receipt delivery - Electronic invoice support - Analytics export to Excel/PDF Output everything step-by-step beginning with: 1. System architecture diagram explanation 2. Backend folder structure 3. Django project setup 4. Database schema 5. Authentication system 6. TRA integration engine 7. Receipt processing flow 8. React frontend setup 9. Deployment infrastructure 10. Production optimization Do not give summaries only. Generate actual implementation-level code and architecture.