Level Up Your Architecture Game with Monolithic Modular - It's Not What You Think

Ever had that moment where your codebase feels like a teenager's room - technically organized but somehow still a mess? That was me six months ago. That's when i came across a thing called as Monolithic Modular Architecture. Despite its boring name, this approach changed everything.

You might be thinking "Oh great, another architecture article..." but I promise you this isn't about preaching the "one true way.". Instead, I want to share how this approach helped me sleep better, and actually enjoy working with our codebase again.

What's Monolithic Modular architecture?

Imagine you're building a house. Traditional monoliths are like having one giant room where everything happens (cooking, sleeping, working - chaos!). On the flip side, microservices are like having separate tiny houses for each activity.

Monolithic Modular?
It's like having one house (easier to maintain and secure) but with well-defined rooms that each serve their purpose (kitchen for cooking, bedroom for sleeping - you get the idea). Each "room" (module) has its own rules and purpose, but they're all under one roof.

In code terms, it looks like this:

The secret sauce? Each module:

• Has its own clear boundary (like walls in our house)
• Manages its own specific business logic
• Can talk to other modules through well-defined doorways (interfaces)
• Shares some common utilities (like how all rooms share the same plumbing)

But here's the best part - at the end of the day, you deploy everything together as one unit. No need to orchestrate multiple services or worry about complex network communication. It's modular where it matters (in your code) and monolithic where it helps (in deployment and operation).

Real Project Structure in Action 👀

Now that we understand the concept, let me show you how we implement this in practice with a real-world example. I'll use a typical e-commerce backend API to demonstrate.

Let me show you how this looks in an actual project. Here's a screenshot from VS Code that'll make things crystal clear:

The Key Parts Explained🎯

1. The modules Directory

Each module is a self-contained feature with its own:
controller.js (🔧 handles HTTP requests)
service.js (⚙️ business logic)
routes.js (🛣️ API endpoints)
index.js (📦 public interface)

2. Supporting Cast

middlewares/: Shared middleware like auth checks and error handlers
utils/: Common utilities (JWT handling, error classes)
prisma/: Database stuff kept neat and tidy

Why This Structure Rocks💡

• Easy to Navigate: Need to fix an auth bug? Just dive into the auth module. Everything you need is right there.
• New Developer Friendly: The structure tells the story. You can understand how the app works just by looking at the folder structure.
• Scalable: Adding a new feature? Create a new module folder, and you're good to go. No need to touch existing code.

Common Gotchas & How to Handle Them 🚧

1. Module Boundaries

• Don't Share Database Models Directly: Instead of importing Prisma models everywhere, expose specific methods through your service
• Avoid Circular Dependencies: If modules A and B need each other, that's a red flag. Usually means you need to rethink your boundaries
• Keep Utils Actually Useful: Don't turn your utils folder into a dumping ground. If it's specific to a module, keep it in that module

2. Dependency Management Tips

• Use Module Index Files Wisely: Export only what other modules need. Not everything needs to be public
• Dependency Injection is Your Friend: Pass services through constructors-makes testing easier and dependencies clear
• Watch for Growing Modules: If a module is getting too big, it might need to be split. Size isn't just about lines of code - it's about responsibility

3. Practical Advice

• Start with broader modules and split when needed - don't over-optimize early
• Keep module names business-focused, not technical (prefer inventory over data-management)
• Document module boundaries in README files - your future self will thank you
• Use consistent file naming across modules - makes the codebase feel professional

Conclusion 🎯

When to Consider This Pattern

• Your monolith is getting messy, but microservices feel like overkill
• You want clean code organization without deployment complexity
• Your team needs clear boundaries but wants to keep things simple
• You're building something that might grow but don't want to over-engineer

Results After Adoption

• 50% faster onboarding for new team members
• Easier to locate and fix bugs
• Better test coverage (modules are naturally more testable)
• Happier developers (seriously, no more "where does this code go?" debates)

The Journey Continues 🚀

This pattern has transformed how I think about architecture. It's not just about organizing code - it's about making development enjoyable and maintenance manageable.

I'm always excited to hear how others are structuring their applications and learn from different approaches. If you found this helpful or have your own experiences to share, let's connect!

Find me at:

🐦 Twitter: @salehdotdev

🌐 Portfolio: salehkhatri.tech

📧 Email: [e-mail]

Follow me for more content about JavaScript, Node.js, and software architecture. I share regular tips and insights about building better applications!

Want to dive deeper into any aspect or need help implementing this in your project? Feel free to reach out - I'm always happy to help fellow developers level up their architecture game! 🎮

Remember: Good architecture isn't about following rules blindly - it's about making development enjoyable and maintenance manageable. Keep building awesome stuff!

Comments

[Anupam Chakrawarti]

Nice article. Have you worked with Next.js the "Full-stack framework"? If so, how does this architecture "Monolithic Modular" translate with regards to front-end, backend and especially with app router?

Also, have you dabbled with FSD architecture, if so, does this go hand-in-hand with "Monolithic Modular"?

🍻

[Saleh Khatri]

Thanks a lot! I’ve worked with Next.js, and I think Monolithic Modular Architecture works well with it. With the App Router (since Next.js 13), you can organize the app directory so each feature has its own folder with routes, components, and API routes, keeping things modular but integrated in the same app.

I haven’t explored FSD architecture yet, but from what I’ve read, it seems to focus on organizing the frontend into layers like features and shared components. It could definitely complement a Monolithic Modular approach, especially for the frontend.

Thanks for the great question—it’s got me curious to learn more about FSD!

[Afaz Khatri]

The article explains the architecture precisely.

This also seems similar to domain driven development which separates domain specific logics separate into its own modules.

[Saleh Khatri]

Thanks for the feedback! You’re absolutely right—Monolithic Modular Architecture does share similarities with Domain-Driven Design. Both focus on organizing code into domain-specific modules, which helps keep things maintainable and scalable. Appreciate the insight!