Full-Stack ArchitecturePayment SystemsREST APIs

Modern
Commerce
Platform

A full-stack e-commerce system engineered with real-world business logic, scalable backend services, and a seamless checkout experience.

01 — The Problem

Most e-commerce apps live in the shallow end.

Beginner e-commerce apps typically display products and call it done. They skip the hard parts — proper checkout validation, real payment workflows, protected routes, order consistency, and a backend architecture that doesn't collapse under real usage.

The gap between a demo project and a production-grade system is where most developers stop. LINEA was built to close that gap.

02 — The Solution

A complete commerce system, engineered end-to-end.

01

Auth System

JWT + Google OAuth for secure session management and protected user flows.

02

Cart & Wishlist

Full state management with persistent cart and user-specific wishlist functionality.

03

Checkout Logic

Multi-step checkout with shipping options, address validation, and total calculation.

04

Order Pipeline

Order creation tied directly to payment intent — no orphaned records.

05

Payment Handling

Mock Stripe intent + webhook confirmation for real-world payment lifecycle simulation.

06

Modular Backend

Controller → Service → Model architecture ensuring clean separation of concerns.

03 — Architecture

Built for clarity and scale.

React FrontendVite + TypeScript
Express API LayerRESTful endpoints
Controllers → Services → ModelsSeparation of concerns
MongoDB DatabaseDocument-based storage
Payment SystemMock Intent + Webhook
04 — Engineering Decisions

Every decision had a reason.

Decision 01

Snapshot-based pricing

Order prices are captured at checkout time, not fetched dynamically — preventing inconsistencies if products change after an order is placed.

Decision 02

Protected API routes

Cart, wishlist, and orders are gated behind JWT middleware — ensuring user data is never exposed without authentication.

Decision 03

Service layer abstraction

All business logic lives in a service layer, making controllers thin and the system easy to test, extend, or replace.

Decision 04

Webhook-based confirmation

Payment status is confirmed via webhook events, not frontend callbacks — preventing race conditions and fake payments.

05 — Performance & Optimization

Fast where it matters.

Reduced redundant API calls through efficient client-side state management

Improved checkout reliability with strict server-side validation rules

Optimized product queries with indexing and filtering at the database layer

Modular API clients for clean separation and easier maintainability

06 — Product Thinking
"The goal wasn't to display products. It was to simulate the full commerce reality."

Real commerce is messy — users abandon checkouts, payments fail, orders need consistency guarantees. LINEA was built with that full complexity in mind. The focus was always on user journey, data consistency, and the backend architecture that holds it together silently.

Not just another portfolio demo. A system that could run in production.

07 — Impact

What this project demonstrates.

Full-StackSystem Design Capability

From auth to payment confirmation — every layer designed and implemented.

ProductionReady Architecture

Patterns and practices that transfer directly into real-world engineering roles.

End-to-EndCommerce Flow

Complete user journey simulation from browsing to order confirmation.

Interested in working together?

Let's build something
that actually works.