The structure problem no one teaches
New Node.js developers hit the same wall: they can write code, but they don't know where it should live. Authentication tutorials and database guides are everywhere. Clear guidance on structuring a backend project is not.
The result: projects that work until they don't. Logic bleeds between layers. Controllers do database queries. Routes contain business rules. Three months in, refactoring means starting over.
The basic flow that works
A beginner-friendly structure follows a clear request path:
Request → Route → Controller → Service → Repository → Data
Each layer has one job. Routes handle endpoints. Controllers manage request/response. Services contain business logic. Repositories touch the database. Separate files for each in folders: routes/, controllers/, services/, repositories/.
This is the MVC pattern with an added service layer. It's prescriptive, which is the point. When you're learning, constraints help.
Stack Overflow's 2025 survey shows Express in roughly 70% of Node backend projects. Most start with this layered approach. The question is what comes next.
When the basic structure breaks down
Type-based organization (grouping by routes, controllers, services) works until your app has 15+ features. Then you're scrolling through massive folders looking for related code. A change to user management means editing files in four different directories.
Enterprise teams in APAC are increasingly adopting feature-based structures instead: group by domain, not by type. A user/ folder contains its own routes, services, and repositories. An order/ folder does the same. This mirrors how microservices think, even in monoliths.
Advanced setups also separate config by component (Redis settings, server config) rather than dumping everything in one file. Environment variables replace hardcoded values. Scripts live in their own folder, not mixed with application code.
The validation question everyone asks
Once structure is sorted, the next decision is validation middleware. Three options dominate: express-validator, Joi, and Zod. Express-validator integrates cleanly but feels dated. Joi has the ecosystem. Zod brings TypeScript-first design and better DX.
For TypeScript projects starting now, Zod is worth the bet. For existing Express apps with Joi already in place, switching costs matter more than marginal gains.
What this means in practice
If you're building your first Node backend, start with the layered structure. Don't skip layers because they feel like overhead. The discipline teaches you separation of concerns.
If your project is growing past 10 features, consider feature-based organization before the refactor becomes expensive. The pattern applies whether you're shipping a startup MVP or building government backend systems.
Node.js powers 2.1% of websites globally (W3Techs, 2025). Most of those started with unclear structure. The ones that scale figured this out early.