Next.js API Routes vs Spring Boot for Solo Developers

Quick Comparison

Next.js API Routes Overview

Next.js API Routes are the simplest way to add backend logic to a Next.js project. Drop a file in app/api/, write a handler, and you have an endpoint. No server configuration, no separate deployment, no additional language to manage.

I reach for API Routes when the backend is secondary to the frontend. Webhook receivers, form handlers, API proxies, lightweight CRUD. For these cases, the unified codebase and single deployment to Vercel makes everything faster. You're not managing infrastructure. You're building features.

The ceiling is lower than a dedicated framework, though. No built-in ORM, no structured middleware pipeline, no background job system. As your backend grows, you'll start wishing you had more guardrails.

Spring Boot Overview

Spring Boot is the Java ecosystem's answer to rapid application development. It wraps the Spring framework with sensible defaults, auto-configuration, and an embedded server so you can get a Java backend running without the XML nightmare that Spring used to require.

Here's the thing about Spring Boot. It's designed for teams, not solo developers. The project structure, the annotation-heavy code, the dependency injection system. All of this makes sense when you have 5 engineers who need clear boundaries and conventions. When you're one person, it feels like wearing a suit to work from home.

That said, Spring Boot is incredibly capable. JPA for database access, Spring Security for auth, Spring Data for repositories, Spring Cloud for microservices. If you need enterprise-grade features like distributed transactions, event sourcing, or complex security policies, Spring Boot has mature, production-tested solutions.

Key Differences

Complexity gap is enormous. Next.js API Routes are functions. Spring Boot is an enterprise framework. A simple REST endpoint in Spring Boot requires a controller class with annotations, a service layer, a repository interface, and entity classes. In Next.js, it's one function in one file.

Memory and startup. A Spring Boot application uses 200-500MB of RAM at baseline and takes 5-15 seconds to start. Next.js API Routes on Vercel start in milliseconds (after cold start) and use whatever the serverless function allocates. For a solo developer paying for hosting, memory usage matters.

Type safety and tooling. Java's type system is excellent, and IntelliJ IDEA provides arguably the best IDE experience in any language. TypeScript with Next.js is good, but Java tooling has decades of polish.

Ecosystem depth. Spring Boot has solutions for virtually every enterprise problem. Security, caching, messaging, batch processing, API documentation. The Node.js ecosystem has equivalents, but they're separate packages with separate documentation and separate maintenance.

Developer velocity. Next.js API Routes are faster to prototype with. Spring Boot is faster to scale and maintain in complex applications. For solo developers, the first month of development speed usually matters more than theoretical scalability.

Deployment. API Routes deploy to Vercel with a git push. Spring Boot needs a JVM host, whether that's a VPS, AWS Elastic Beanstalk, or a container platform. More infrastructure to manage.

When to Choose Next.js API Routes

• You're already building with Next.js and need a simple backend
• Speed of development is the top priority
• You want minimal infrastructure management
• Your API is straightforward CRUD operations
• You prefer JavaScript/TypeScript over Java

When to Choose Spring Boot

• You're building a complex backend with many integrations
• You already know Java/Kotlin well
• Enterprise features like distributed transactions are genuinely needed
• You're building for a domain where Java libraries are strongest (finance, insurance)
• Long-term maintainability with strict typing is worth the upfront cost

The Verdict

I'll be direct. For solo developers, Spring Boot is almost never the right choice. The overhead is designed for teams and enterprise contexts. You'll spend more time on annotations, configuration, and boilerplate than on building your product.

Next.js API Routes aren't perfect either. They're limited for complex backends. But that limitation actually helps solo developers. It forces you to keep things simple, which is usually the right call when you're building alone.

If you need more than API Routes can offer but don't want Spring Boot's weight, look at frameworks like Django, Laravel, or even a standalone Hono or Express server. They sit in the sweet spot between "too simple" and "too enterprise" that most solo developers actually need.

Pick Spring Boot only if you're already a Java developer who thinks in Spring annotations. Otherwise, the learning curve and boilerplate will slow you down considerably.