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Case study / 07
A complete production-grade e-commerce platform for jewelry retail - two Next.js frontends (customer storefront with Material-UI + admin dashboard with Tailwind CSS), an Express.js API, Stripe payment processing, transactional emails via Brevo, and automated PDF invoice generation.
01 / System behavior
A project-specific technical mechanism based on the recorded architecture and implementation context.
Built as a graduation project, this platform deliberately chose ambition over simplicity - not a CRUD app with a login page, but a full production-grade system where you have to think about payment security, email deliverability, image optimization, multi-role access control, and webhook idempotency.
The Stripe integration handles the full payment lifecycle: the API creates Checkout Sessions with line items and metadata, Stripe redirects to their hosted payment form, and webhooks drive the actual order status. The key insight baked into the implementation: never trust the client-side redirect - only the verified webhook signature is the reliable signal. Every webhook is verified using stripe.webhooks.constructEvent(), and the handler checks idempotency to prevent processing the same payment event multiple times.
03 / Architecture record
A structured reading of the architecture recorded with this project.
Three applications working together:
• Customer Storefront (magazin/) - Next.js 14 + Material-UI for product browsing, cart management, and Stripe checkout • Admin Dashboard (admin/) - Next.js 14 + Tailwind CSS for product management, order processing, analytics, and invoice generation • Backend API (server/) - Express.js with Sequelize ORM handling business logic, JWT auth, Stripe webhooks, Brevo emails, and PDFKit invoices
The API connects to PostgreSQL via Sequelize with a rich relational schema including hierarchical categories (parentId self-referencing). Stripe handles payment flow with webhook-driven order status updates. Brevo dispatches transactional emails. PDFKit generates invoices on-demand.
Docker Compose orchestrates the entire stack for local development. GitHub Actions CI/CD pipeline handles testing and deployment.
Transactional emails (order confirmations, shipping notifications, password resets) flow through Brevo with templated inline-CSS HTML that degrades gracefully across email clients including Outlook.
When an admin marks an order as shipped, the system generates a PDF invoice on-demand using PDFKit - streamed directly to the browser with no file storage. A custom table renderer handles column widths, alternating row backgrounds, and automatic page breaks.
The security stack includes: bcrypt with 12 salt rounds, JWT with 15-minute access tokens and single-use refresh token rotation, Helmet.js security headers, rate limiting on auth endpoints, parameterized queries via Sequelize, CORS with strict origin whitelisting, and Joi schema validation on every endpoint.
05 / Selected highlights
The decisions and workflows that carry the most explanatory weight.
06 / Supported metrics
TypeScript, Next.js, React, Express.js, Sequelize, PostgreSQL, Stripe, Brevo, PDFKit, Material-UI, Tailwind CSS, JWT, Docker, Mocha/Chai, Supertest, Selenium
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