If you’ve ever built Java backend apps, you’ve probably touched Spring. But if you're trying to choose between Spring and Spring Boot, here’s my honest take after working with both:
🧱 Spring – Full Control, More Work
Spring (core framework) is powerful — no doubt. You get to configure things exactly the way you want. From defining beans in XML (or Java config), to handling your own server setup, security, and data layers — everything is in your hands.
💡 Good for:
Legacy systems that need integration with custom infrastructure
Teams that want to manage every layer of the stack
Environments with strict requirements around deployment and configuration
But with that power comes verbosity. Want a simple REST API? You’re writing multiple files just to get started.
⚡ Spring Boot – Convention Over Configuration
Spring Boot was a game changer for me.
It doesn’t replace Spring — it builds on top of it. It just makes getting started easier with:
Auto-configured beans
Embedded Tomcat/Jetty/Undertow
Sensible defaults for almost everything
Production-ready tools like /actuator endpoints for health checks and metrics
With Boot, I’ve spun up microservices in minutes. Just write your controller, annotate a few classes, and run the app. No need to deploy to an external server — it's self-contained.
💡 Perfect for:
Microservices
Internal tools
APIs where speed and simplicity matter
Rapid prototyping or MVPs
| If you're... | Use Spring | Use Spring Boot |
|----------------------------------|------------|-----------------------------|
| Building a large monolithic App | ✅ | ✅ (with caution) |
| Integrating with legacy systems | ✅ | ❌ |
| Building microservices | ❌ | ✅ |
| Prototyping an idea fast | ❌ | ✅ |
| Need full control over configs | ✅ | ❌ |
| Want to write less boilerplate | ❌ | ✅ |⚙️ A Few Gotchas
Spring Boot’s autoconfiguration is amazing… until it isn't. Debugging what Boot is doing behind the scenes can take time.
In very complex apps, you might find yourself undoing Boot’s decisions — that’s when vanilla Spring could be better.
Spring Boot is NOT “less powerful” — it's still full Spring under the hood. It just adds opinionated defaults.
💬 Final Thoughts
For me, Spring Boot is now the default unless there’s a specific reason to go vanilla Spring. I still love the control Spring gives, but when speed, simplicity, and clean code matter, Boot wins every time.
It’s not Spring vs Spring Boot — it’s really Spring and Spring Boot. Know when to use what.
Would love to hear how others are using Spring in real-world projects! Are you still using plain Spring in 2025, or has Boot become your go-to?
