Inventory & Purchase Order System

Project Description

This system was designed for a manufacturing business that needed to bring full control over its inventory and procurement workflow into one platform — replacing spreadsheets and manual tracking with a structured, auditable digital process. The entire Purchase Order lifecycle is handled in-system: from initial raise through supplier confirmation, goods receipt, and automatic stock update — with every action logged for a complete audit trail.

The technical focus was on reliability, real-time visibility, and financial integrity. SignalR WebSockets keep delivery status synced every 30 seconds without page refreshes. Stripe handles payments with webhook-verified event processing. Clean Architecture ensures the business logic remains testable and isolated from infrastructure concerns as the system scales.

Key Highlights

• 4-level RBAC with JWT — Admin, Purchase Manager, Store Manager, Staff — Designed a multi-role permission system where each access level sees only the modules and actions relevant to their function. JWT claims carry role and tenant context; every API endpoint is protected with policy-based authorization — no role can escalate or cross access boundaries.
• Complete Purchase Order workflow with full audit trail — Built the end-to-end PO lifecycle: Purchase Manager raises PO → Supplier confirms → Goods received at warehouse → Stock levels auto-updated. Every state transition is timestamped and attributed to a user, creating an immutable audit trail covering who approved what and when.
• Stripe Payment Gateway — ₹2Cr+ monthly transaction volume — Integrated Stripe Checkout for secure supplier and client payments with webhook-based event verification to confirm payment success before updating order status — handling over ₹2 crore in monthly transaction volume with zero payment-status mismatches.
• Real-time order tracking with SignalR WebSockets — Implemented a SignalR Hub that pushes delivery status updates to connected clients every 30 seconds — eliminating the need for manual page refreshes on the order tracking dashboard and keeping warehouse staff, managers, and admins all in sync simultaneously.
• Real-time stock level dashboard — Built a live inventory dashboard displaying current stock levels, reorder point thresholds, and low-stock indicators using colour-coded alerts (green / amber / red) — giving Store Managers an instant visual snapshot of inventory health without running reports.
• Automated low-stock alerts — MailKit & Twilio — Implemented a background monitoring service that checks stock levels against minimum thresholds and automatically triggers email alerts via MailKit and SMS via Twilio when items fall below reorder points — ensuring procurement action is taken before stockouts occur.
• Clean Architecture — strict separation of concerns — Structured the solution into Domain, Application, Infrastructure, and Presentation layers following Clean Architecture principles. Business rules live in the Domain layer with zero infrastructure dependencies; all external concerns (DB, email, payment) are behind interfaces — making the core logic fully unit-testable.
• EPPlus — Excel inventory & PO reports — Integrated EPPlus to generate detailed Excel exports for inventory snapshots, PO history, and supplier performance reports — with column formatting, data validation, and summary rows built in — used daily by the procurement and finance teams.