System Requirements Document for Billing Software

1. Introduction

This document outlines the system requirements for the "Billing Software" project, which aims to develop a Restaurant POS Billing MVP. The focus is on creating a simple, efficient, and user-friendly web application for restaurant billing.

2. System Overview

The "Billing Software" project is designed to facilitate efficient order processing and sales management in a restaurant setting. It provides a POS interface for cashiers and owners to manage sales and menu items, ensuring a seamless billing experience.

2a. Product Interpretation and Delivery Boundary

• Domain Descriptor: Restaurant POS System

  • Source Evidence: User specification
  • Confidence: 0.95

• What is being built: A restaurant billing web app where a cashier selects menu items and quantities, sees a live invoice, confirms the bill, prints it, and the sale is saved. The owner can manage the menu and view sales.

• Excluded Assumptions: Inventory management, Kitchen display systems, CRM features, Online ordering integrations.

• Access: Application-owned identity with authentication required for restaurant owner/cashier.

• Behavior Contracts:

  • Bill Creation and Printing: Triggered by cashier clicking "CONFIRM & PRINT", resulting in invoice generation, order saving, and print dialog opening.
  • Menu Management: Owner can add/edit categories and menu items.
  • View and Reprint Bills: Cashier can view and reprint invoices.

2b. Page Content and Component Coverage

• POS Screen:

  • Left Side: Search items, category buttons, menu item buttons/cards, item name and price.
  • Right Side: Current bill/cart, selected item, quantity controls, item total, subtotal, discount, tax, grand total, payment method, "CONFIRM & PRINT" button.

• Bill Creation: Process for confirming and printing bills.

• Invoice Generation: Clean print-friendly restaurant receipt.

• Bills Page: Shows invoice details and allows reprinting.

• Owner Dashboard: Displays sales data with filters for Today/This Week/This Month.

3. Functional Requirements as Story Points

• As a Cashier, I should be able to select menu items and quantities, see a live invoice, and confirm the bill to print it.
• As a Cashier, I should be able to view and reprint invoices from the Bills page.
• As an Owner, I should be able to manage the menu by adding, editing, and deleting categories and items.
• As an Owner, I should be able to view sales data on the dashboard with filters for different time periods.
• As a Cashier, I should be able to log in to access the POS system.
• As an Owner, I should be able to log in to manage the menu and view sales data.

4. User Personas

• Owner: Manages the menu, views bills, and accesses the dashboard.
• Cashier: Creates bills, views bills, and prints/reprints bills.

5. Core User Flows

Cashier Flow

1. Log in to the system.
2. Open the POS screen.
3. Select menu items and adjust quantities.
4. Confirm and print the bill.
5. View and reprint invoices from the Bills page.

Owner Flow

1. Log in to the system.
2. Manage menu items and categories.
3. View sales data on the dashboard.

6. Visuals Colors and Theme

• Primary: #3498db (blue)
• Primary Light: #5dade2
• Secondary: #2ecc71 (green)
• Accent: #e74c3c (red)
• Highlight: #f1c40f (yellow)
• Background: #ecf0f1 (light gray)
• Surface: #ffffff (white)
• Text: #2c3e50 (dark gray)
• Text Muted: #95a5a6 (gray)
• Border: #bdc3c7 (light gray)

7. Signature Design Concept

The POS screen will feature a clean and modern design with large, easy-to-click buttons for menu items and clear quantity controls. The live invoice will be prominently displayed on the right side, with a large "CONFIRM & PRINT" button for easy access. The design will prioritize speed and usability, ensuring a responsive layout for both desktop and tablet use.

8. Interaction Model & Motion Direction

• POS Screen: Animated interaction model with moderate scroll-triggered reveals and hover transitions for a polished user experience.
• Dashboard and Bills Page: Static interaction model prioritizing clarity and data presentation.

9. Non-Functional Requirements

• Performance: The application must be extremely fast and responsive.
• Usability: The UI should be clean and modern, with a focus on ease of use for cashiers and owners.

10. Tech Stack

• Frontend: React/Next.js, TypeScript, Tailwind CSS
• Backend: Supabase PostgreSQL
• Authentication: Supabase Auth

11. Assumptions and Constraints

• The system will not include features such as inventory management, kitchen display systems, CRM, or online ordering integrations.
• The application will be developed as a web app, not a mobile app.

12. Glossary

• POS: Point of Sale
• MVP: Minimum Viable Product
• GST: Goods and Services Tax
• UPI: Unified Payments Interface

This document serves as a comprehensive guide for the development of the "Billing Software" project, ensuring all specified requirements are met without the addition of extra features.