An e-commerce backend needs to handle products, carts, orders, and payments while keeping the data consistent even when multiple users are shopping simultaneously. As the creator of CoreUI with 25 years of backend development experience, I’ve built the API layers for several commercial e-commerce platforms and the most important architectural decision is keeping cart state on the server to prevent inventory inconsistencies. The core data model links products, carts, orders, and users, and the API surface exposes clean REST endpoints for each resource. This guide focuses on the critical cart-to-order transition — the most complex part of any e-commerce backend.

A notes API extends the basic CRUD pattern with user ownership — each note belongs to a specific user and only that user can read, update, or delete it. As the creator of CoreUI with 25 years of backend development experience, I use this pattern as the template for any user-scoped resource API in Node.js. The key difference from a public API is that every query includes a userId filter from the JWT payload, ensuring users can never access each other’s data. This requires authentication middleware and a data model that links notes to users.

Building a todo API is the ideal first Node.js project because it covers every fundamental backend concept: creating, reading, updating, and deleting resources with a clean REST interface. As the creator of CoreUI with 25 years of backend development experience, I use this exact project structure as the starting point for more complex Node.js APIs. The key is using Prisma as the ORM for type-safe database access and adding input validation with Zod before any data touches the database. This combination gives you reliable data integrity and TypeScript-compatible queries from day one.