B2B Electronic Invoicing & Billing
A comprehensive B2B Electronic Invoicing & Billing Platform for enterprise-level financial operations.
Use Cases
Businesses can create invoices manually with dynamic line items, product catalogs, and customer selection, or set up automated recurring billing subscriptions for monthly, quarterly, or yearly billing cycles. The system automatically calculates subtotals, tax amounts, and total amounts based on configured VAT rates and currency settings. Users can track invoice statuses (Draft, Pending, Paid, Overdue, Cancelled) with visual indicators, mark invoices as paid, edit existing invoices, and download professional PDF invoices. The platform includes comprehensive customer management with company profiles, product catalogs for quick invoice item selection, and a dashboard showing total revenue, overdue amounts, active clients, and recent activity. Perfect for accounting firms, SaaS companies, service providers, and businesses requiring automated billing workflows with compliance-ready documentation.
Key Features
- Invoice Management with manual creation, editing, and deletion
- Automated Recurring Billing with monthly/quarterly/yearly cycles
- Customer & Company Profile Management with full CRUD operations
- Product Catalog with quick invoice item autofill
- PDF Invoice Generation with professional QuestPDF templates
- Payment Status Tracking (Draft, Pending, Paid, Overdue, Cancelled)
- Multi-currency Support with configurable currency settings
- VAT/Tax Calculation with automatic amount computation
- Real-time Dashboard with revenue analytics and recent activity
- Overdue Payment Notifications and tracking
- RESTful API for external system integration
Architecture
Built with a RESTful API-first architecture using ASP.NET Core Web API (.NET 8.0) on the backend and Angular 17+ with TypeScript on the frontend. The system follows a modular structure with clean separation between invoice management, customer management, product catalogs, subscription billing, and PDF generation modules. The backend uses MongoDB for flexible document storage with MongoDB.Driver, implements background services for automated recurring billing, and includes QuestPDF for professional invoice PDF generation. The frontend uses component-based architecture with Angular standalone components, reactive forms for complex invoice editing, and a macOS-inspired UI design with TailwindCSS and SCSS. This architecture enables seamless integration with external accounting systems, supports future mobile app development, and ensures scalability through optimized database queries and efficient background job processing.
Security & Performance
Security is implemented through JWT-based authentication (configured with Microsoft.AspNetCore.Authentication.JwtBearer) for secure API access, with CORS protection configured for secure cross-origin requests between frontend and backend. The system includes comprehensive error handling and logging for security tracking and debugging. Performance is optimized through efficient MongoDB queries with proper indexing, enabling fast data retrieval even with large invoice volumes and extensive customer databases. The backend uses background services (IHostedService) for asynchronous recurring billing processing, preventing blocking operations. Static file handling is optimized for the Angular frontend, and the system is built to handle high traffic with scalable MongoDB architecture and efficient PDF generation using QuestPDF with native Linux dependencies.
Development & Deployment
The backend is fully dockerized using Docker with multi-stage builds for .NET 8.0, ensuring consistent development and production environments. The frontend uses Nixpacks for Railway deployment without Docker, with automated build and serve processes. The codebase follows TypeScript for full type safety on the frontend and .NET 8.0 best practices with nullable reference types enabled. The system is structured for automated CI/CD pipelines and deployed cloud-natively on Railway with MongoDB database. The responsive macOS-inspired design ensures optimal user experience with glassmorphism effects, soft shadows, and smooth animations. The frontend is built using Angular CLI for fast development and production builds, while the backend is served with ASP.NET Core Kestrel for production-grade performance. The entire system supports environment-based configuration with Railway environment variables for database connections and CORS origins.