NAME
EZOO POS System — POS and inventory backend for Rayon Energy built with FastAPI and PostgreSQL, using Decimal arithmetic for financial precision and immutable audit trails.
SYNOPSIS
DESCRIPTION
Repository: GitHub - M-Alhbyb/ezoo_pos
EZOO POS is a backend-focused point-of-sale and inventory system built for Rayon Energy, a company specializing in solar equipment and electrical supplies.
The system uses FastAPI with async database operations for concurrent usage.
Financial calculations use Decimal arithmetic instead of floating-point to prevent precision errors in VAT, fees, and transaction totals.
The project includes inventory management, transaction processing with immutable sales records, fee calculations, VAT support, and structured validation with Pydantic schemas.
The backend enforces explicit business rules, data consistency, and backend authority over all calculations and validations.
TECH STACK
ARCHITECTURE
Modular FastAPI architecture with separated API, schema, model, and service layers. PostgreSQL as the primary source of truth for inventory and financial operations. Async SQLAlchemy integration using asyncpg. Alembic migration system for schema versioning. Decimal-based financial calculations for transaction precision. WebSocket-ready architecture for future real-time POS synchronization.
BUGS / CHALLENGES
Preventing floating-point precision errors in financial workflows. Designing immutable transaction records suitable for audit trails. Maintaining data integrity during concurrent async operations. Structuring reusable calculation systems for fees and VAT.
EXIT STATUS / OUTCOMES
Delivered reliable financial calculation workflows using Decimal precision. Established immutable transaction records for auditability. Built API architecture supporting retail POS operations.