🚫 Why You Shouldn’t Use Next.js as a Fullstack Framework (and When You Should)

Next.js is excellent for UI — especially when you need SSR/SSG or fast iteration.
For small-to-medium apps, dashboards, landing pages, or MVPs, using it as a fullstack monolith is totally fine.

But as your application grows in complexity, using Next.js for both Frontend and Backend starts to work against clean architecture.

Why this becomes a problem:
• Frontend and backend are deployed together (shared failure domain)
• UI code and business logic tend to mix over time
• You can’t scale backend independently
• Domain services / workflows don’t fit cleanly into the Next.js runtime
• Monitoring, caching, and background processes get tightly coupled to the framework

In enterprise systems, we usually want:
✅ Clear separation of concerns
✅ Independent FE and BE deploys
✅ Well-defined domain boundaries
✅ Backend freedom (NestJS, Spring Boot, Go, etc.)

This is why many teams who use Next.js end up treating it primarily as:

A Frontend Framework
(UI + routing + SSR)
while keeping the backend as a separate service.

So my perspective is simple:
👉 Next.js is great for UI.
❌ Not always the right choice as a "fullstack" replacement for complex or long-lived systems.

If any project that was made as a fullstack by NextJS alone, if grows too big, needs to decouple its backend logic to a seperate server.
Preferably in a technology specialized in Backend (like Springboot, NestJS, .NET, etc)

Curious to hear your experiences:
Do you agree? and have you seen a Next.js fullstack codebase scale cleanly beyond the MVP stage?