Case study
GIMS
Grain inventory & merchant trading system
Store-scoped trading and inventory platform for grain merchants — warehouses, purchases, partial GRNs, sales with COGS, stock movements, OTP security, and dual web + JWT API access.
Product overview — full frame
01 — Challenge
The problem we solved
- Fragmented stock and billing for trading merchants
- Weak COGS and warehouse visibility
- Need approval-based store onboarding and secure auth
02 — Goals
What success looked like
- Unified inventory + trading domain
- Accurate stock movements and COGS
- Web portal + API for future mobile
- OTP and store approval security
03 — Signals
Capability profile
Measured strengths across delivery, innovation, and operational maturity.
Trading-grade
Domain depth
JWT dual access
API readiness
OTP + approval
Security posture
CI SSH
Deploy automation
04 — System design
Architecture
Django monolith with dual surfaces
Shared domain layer serving Django templates and DRF/JWT APIs. Multi-tenant by Store with approval workflow before portal use.
- 101
Surfaces
Layer 1 of 4Django templatesDRF + SimpleJWTPDF docs - 202
Domain
Layer 2 of 4Warehouse stockPurchasesSalesLedger - 303
Security
Layer 3 of 4Email OTPStore approvalRole gates - 404
Ops
Layer 4 of 4Gunicorn/systemdNginx mediaGitHub Actions SSH
05 — Stack
Technology stack
Production tools powering this product — icons for quick recognition.
Python
Django
PostgreSQL
Nginx
GitHub Actions
06 — Capabilities
Key features
Multi-warehouse stock with movement audit
Purchase receipts (partial GRNs) & sales dispatch
Average cost / unit_cost_at_sale for COGS
Session web auth + JWT API
ReportLab PDFs and dark/light UI
07 — Deep dive
Structure & detail
Inventory semantics
| Flow | Models | Outcome |
|---|---|---|
| Inbound | Purchase → Receipt items | Partial GRNs update stock |
| Outbound | Sale → Dispatch items | Partial fulfillments |
| Audit | StockMovement | Purchase/sale/transfer/adjust |
| Costing | avg cost + unit_cost_at_sale | Reliable COGS |
08 — Outcomes
Business impact
Merchant clarity
One operational system for stock and billing
Financial accuracy
COGS-aware sales and movement audit
Roadmap
Structured for multi-store SaaS and mobile clients
Closing note
Production grain inventory platform that replaces spreadsheet chaos with warehouse-aware trading workflows and API extensibility.
