Invoice Generator System Requirements Document

1. Introduction

The Invoice Generator project is a modern, scalable, and secure SaaS application designed for freelancers, agencies, consultants, and small businesses. It aims to streamline the invoicing process by providing a comprehensive set of features for creating, managing, and tracking invoices.

2. System Overview

The Invoice Generator is built with a robust tech stack to ensure scalability, security, and responsiveness. It follows clean architecture and best coding practices to deliver a production-ready application. The system supports various functionalities, including user authentication, invoice management, customer and product management, and detailed reporting.

3. Functional Requirements as Story Points

• As a User, I should be able to register an account using email and password.
• As a User, I should be able to log in using email and password.
• As a User, I should be able to reset my password if forgotten.
• As a User, I should be able to verify my email address.
• As a User, I should be able to log in using Google OAuth.
• As a User, I should be able to view and edit my profile.
• As a User, I should be able to change my password.
• As a User, I should be able to view a dashboard showing total revenue, invoices created, paid invoices, pending invoices, overdue invoices, recent activity, and a monthly revenue graph.
• As a User, I should be able to perform CRUD operations on customers with fields such as name, email, phone, GST number, address, city, state, country, pincode, and notes.
• As a User, I should be able to search, paginate, and export customer data to CSV.
• As a User, I should be able to perform CRUD operations on products with fields such as name, description, price, tax %, HSN code, and category.
• As a User, I should be able to create invoices with auto-generated invoice numbers, invoice date, due date, customer selection, multiple line items, discounts, tax, notes, terms & conditions, company logo, and signature.
• As a User, I should be able to manage invoice status (draft, sent, paid, overdue, cancelled).
• As a User, I should be able to generate professional PDFs for invoices.
• As a User, I should be able to email, download, duplicate, and print invoices.
• As a User, I should be able to mark invoices as paid, record partial payments, and view payment history.
• As a User, I should be able to view reports on monthly revenue, pending amounts, top customers, top products, revenue charts, and invoice counts.
• As a User, I should be able to configure settings for company profile, company logo, GST number, business address, invoice prefix, invoice number format, currency, tax settings, and dark mode.
• As a User, I should be able to use recurring invoices, invoice templates, multi-language, multi-currency, client portal, expense tracker, dashboard widgets, CSV export, Excel export, QR code on invoice, barcode support, and integrate with Razorpay and Stripe.

4. User Personas

• Freelancer: Individual users who need to generate invoices for their clients.
• Agency: Small to medium-sized agencies managing multiple clients and projects.
• Consultant: Professionals providing consultancy services and requiring detailed invoicing.
• Small Business Owner: Entrepreneurs managing their business finances and client billing.

5. Core User Flows

• User registers -> verifies email -> logs in -> sets up company profile -> creates customer -> creates product -> generates invoice -> sends invoice -> tracks payment status.
• User logs in -> views dashboard -> accesses reports -> adjusts settings -> logs out.

6. Visuals Colors and Theme

• primary: #1E40AF (Indigo)
• primary_light: #3B82F6 (Light Blue)
• secondary: #10B981 (Green)
• accent: #F59E0B (Amber)
• highlight: #EF4444 (Red)
• bg: #F3F4F6 (Gray)
• surface: #FFFFFF (White)
• text: #111827 (Dark Gray)
• text_muted: #6B7280 (Gray)
• border: #D1D5DB (Light Gray)

7. Signature Design Concept

The Invoice Generator's landing page will feature an interactive "Invoice Journey" animation. Users will see a digital invoice being created in real-time, with line items being added, totals calculated, and the invoice being sent to a client. This animation will be interactive, allowing users to click on different parts of the invoice to see detailed information about each section. The animation will use motion/react for smooth transitions and interactions, creating an engaging and educational experience for users.

Landing Hero Motion Brief

The hero section will showcase an animated sequence where a blank invoice template is populated with data (e.g., client details, line items, totals) as the user scrolls. The sequence will loop every 10 seconds, demonstrating the transformation from a draft to a finalized invoice. The animation will be built using motion/react and CSS for a seamless experience. The first frame will display a clean, professional invoice layout with a call-to-action to start creating invoices.

8. Interaction Model & Motion Direction

• Interaction Model: Animated
• The landing page will feature moderate scroll-triggered reveals and hover transitions, with spring physics on interactive elements to enhance user engagement.

9. Non-Functional Requirements

• The application must be responsive and work seamlessly across all devices.
• The system must handle concurrent users efficiently and scale as needed.
• All data must be securely stored and transmitted.
• The application must be easy to maintain and extend.

10. Tech Stack

• Frontend: React 19, Vite, TypeScript, Tailwind CSS, React Router, TanStack Query, React Hook Form, Zod, Shadcn UI, Lucide Icons
• Backend: Node.js, Express.js, TypeScript, Prisma ORM, PostgreSQL, JWT Authentication, bcrypt, REST API
• Deployment: Docker, Docker Compose, Nginx
• Storage: Cloudflare R2
• PDF Generation: PDFKit
• Authentication: JWT Access Token, Refresh Token, Google OAuth Login

11. Assumptions and Constraints

• The application will primarily serve users in India, with support for INR currency.
• The system will use PostgreSQL for database management.
• The application will be deployed using Docker and Nginx for scalability and reliability.
• The application will adhere to security best practices, including rate limiting and input sanitization.

12. Glossary

• CRUD: Create, Read, Update, Delete
• JWT: JSON Web Token
• ORM: Object-Relational Mapping
• REST API: Representational State Transfer Application Programming Interface
• SaaS: Software as a Service

This document outlines the requirements and specifications for the Invoice Generator project, ensuring a comprehensive understanding of the system's capabilities and design.