Quotation, Order, and Billing Management System

Overview #Personal Development

A web-based business operations system that centrally manages the entire commercial flow from Quote through Order, Delivery, Invoice, and Payment as mutually referenceable Records. You can track when a project was ordered at which Quote Version, what was delivered, and how much payment was received against which invoice.

Main Features

• Dashboard: Aggregates this month's order amount, invoice amount, payment amount, outstanding receivables, overdue amount and count, and quote conversion rate from actual Records
• Commercial Flow Pipeline: Displays "Quote → Order → Delivery → Invoice → Payment" across projects in a single view
• Quote Management: Multiple line items, Version history, status management (Draft, Sent, Approved, Rejected, Expired)
• Order Management: Duplicates customer, line items, and amount from approved quotes; manages order date, delivery date, and delivery progress
• Delivery Management: Records quantity for each order line item as independent Records; supports partial and multiple deliveries
• Invoice Management: Creates invoices from orders or undelivered items; displays statuses including Issued, Awaiting Payment, Partially Paid, Paid, Overdue, Cancelled
• Payment Management: Links payment date, amount, method, and notes to invoices; tracks multiple payments and full settlement
• Customer and Product Management: Registers and manages customer information and products/services
• Report Printing: Saves A4 print layouts for quotes and invoices directly to PDF from the browser
• CSV Export: Outputs customers, orders, invoices, and payments as UTF-8 CSV
• Operation History: Displays audit Records generated by business commands in chronological order
• Role Switching: Switches between Sales, Accounting, and Administrator roles in the demo; validates permissions at both UI and command layers

Characteristics

• Quote Versioning: Does not overwrite quotes for the same project; manages them as separate Records like Version 1, 2, 3. Retains revision sources and allows confirmation of past conditions, amounts, and statuses
• Accurate Amount Calculation: Maintains all amounts as integers in Japanese yen. Normalizes quantities, performs BigInt calculations, applies consumption tax rounding per tax category, and uses the largest remainder method for allocation to ensure line item totals perfectly match report totals
• Protected Reference Relationships: Prevents cancellation of orders with existing deliveries or invoices; rejects double-invoicing of the same delivery; strictly validates data integrity
• Demo Mode: Includes fictional company, customer, and transaction data from initial display. Input content is saved to the browser's localStorage; administrators can reset the demo to its initial state from the operation history screen

Target Users

• Companies that want to visualize and track the commercial flow from quote to payment
• Developers who want to learn Quote to Cash process design and operational experience
• Those seeking reference implementations for frontend patterns in business systems