Context

I led the design, development, deployment, and long-term maintenance of a fully custom web-based CRM and invoicing platform built from scratch.

The system was created to replace fragmented spreadsheet-driven workflows and serve as the central operational backbone for customer management, product configuration, pricing logic, invoicing, and accounting-related processes.

I acted as the technical lead and primary owner of the project, responsible for architecture, backend, frontend, deployment, and production stability.

Business Challenge

The company required a system capable of handling complex and highly variable business rules, including:

• Customer-specific product pricing
• Variable tax configurations
• Discount structures and special agreements
• Accurate net / gross calculations
• Automated invoice generation
• Accounting consistency across transactions

Each customer could have different pricing rules, tax treatments, and discount agreements. All calculations had to be performed automatically and deterministically at invoice generation time. Even minor financial miscalculations could create accounting inconsistencies, so correctness was critical.

What I Designed And Built

• Full system architecture from scratch
• Backend pricing engine handling dynamic, customer-specific rules
• Automated tax, gross, and net calculation logic
• Invoice generation workflows with validation safeguards
• Database schema designed for financial integrity
• Web-based frontend application for non-technical operational staff
• Validation layers to prevent inconsistent accounting states
• Separation of business logic from presentation layer to ensure maintainability

Impact

• Replaced manual and spreadsheet-based invoicing workflows
• Eliminated recurring human errors in tax and pricing calculations
• Standardized pricing logic across customers
• Centralized operational and financial data
• Provided a scalable internal platform capable of long-term evolution
• Reduced operational friction for non-technical staff