Happy Art Supplies
E-Commerce Platform
A 10-module e-commerce backend with triple-layer auth and an admin engine that ships changes without redeployments.
Overview
The story behind it
Happy Art Supplies is a production e-commerce platform selling art supplies online. I designed and launched its entire backend — a 10-module system covering catalog, cart, orders, inventory locks, reviews, coupons, shipping zones, invoicing, notifications, and admin operations.
Security was a first-class requirement, not a feature toggle. The platform authenticates customers through three composable layers — JWT sessions for the API, OAuth 2.0 social login for friction-free signup, and Email OTP verification for sensitive actions — all feeding one role-based access control system that keeps customer, staff, and admin capabilities strictly separated.
The most impactful piece for the business turned out to be the admin configuration engine: an 8-facet dynamic system that lets non-technical stakeholders update banners, promo codes, loyalty tiers, shipping zones, and storefront copy without a code deployment. Store campaigns that used to need a developer now go live in minutes.
What it does
Key features
- 10-module commerce core — catalog, cart, orders, inventory, reviews, coupons, shipping, invoicing, notifications, admin
- Triple-layer authentication — JWT, OAuth 2.0 social login, and Email OTP unified under one RBAC model
- Inventory integrity — atomic stock locks prevent overselling during concurrent checkouts
- Zone-based shipping — dynamic rates computed per delivery zone, weight class, and order value
- Automated invoicing — programmatic PDF invoices generated post Razorpay checkout with order snapshots
- 8-facet admin engine — banners, promo codes, loyalty tiers, and storefront copy editable without code deploys
How it's built
Architecture & implementation
- Checkout uses MongoDB optimistic concurrency — inventory locks decrement stock atomically and expire on abandoned orders
- Razorpay order creation and signature verification wrap every payment path; invoices render from immutable order snapshots
- Admin configuration documents are versioned with published/draft states so storefront changes roll out atomically and roll back instantly
- Cloudinary pipelines handle product media with on-the-fly transformations, keeping origin storage flat
- Restocking alerts run on inventory thresholds with debounced notification batches to avoid alert storms
- Nginx + PM2 on AWS EC2 with gzip, static caching, and structured request logs per order id
Highlights
Engineering highlights
- Triple-layer auth: JWT, OAuth 2.0 social login, and Email OTP with RBAC
- Dynamic zone-based shipping and automated inventory adjustments with restocking alerts
- 8-facet admin engine — banners, promo codes, loyalty tiers without code redeployments
Takeaways
Lessons learned
- Atomic inventory operations are the difference between a store that scales and one that oversells during its first campaign
- Giving non-technical stakeholders a safe configuration surface multiplies the team's velocity more than any framework choice
- Immutable order snapshots keep invoices, refunds, and disputes consistent even as catalogs change underneath