# Requirements: I Want To Build A Saas Invoicing Tool

## Functional Requirements

### Core Features
1. **User Management**
   - User registration and authentication
   - Profile management
   - Role-based access control

2. **Primary Functionality**
   - Invoice creation and management
- Client management and billing
- PDF generation and email delivery
- Payment tracking and reminders

3. **Data Management**
   - Secure data storage
   - Data validation and sanitization
   - Backup and recovery

## Non-Functional Requirements

### Performance
- Page load times < 2 seconds
- API response times < 500ms
- Support for 1000+ concurrent users

### Security
- HTTPS only
- Input validation
- SQL injection prevention
- XSS protection
- Authentication token security

### Usability
- Responsive design (mobile, tablet, desktop)
- Accessibility (WCAG 2.1 AA)
- Intuitive user interface
- Clear error messages

### Reliability
- 99.9% uptime
- Graceful error handling
- Data integrity
- Automated backups

## Technical Constraints
- Must use modern web technologies
- Database agnostic design
- RESTful API design
- Cloud deployment ready
- Docker containerized

## Compliance
- GDPR compliance for EU users
- Data retention policies
- Privacy policy implementation
- Terms of service

Generated: 2025-02-09 18:21:45