Spring Boot is powerful, flexible, and quick to get started with — but it's also easy to misuse. From bloated controllers to silent performance killers, small mistakes can snowball fast in production.

Spring Boot best practices encompass a range of strategies for building robust, maintainable, and scalable applications. Whether you're building microservices, APIs or full-stack Java applications, these 12 Spring Boot best practices will help you write cleaner, faster, and more scalable code.

Let's dive in !!!

1. 🚀 Use Constructor Injection (Not Field Injection)

Why it matters: Constructor injection is more testable, immutable, and makes dependencies explicit.

// ✅ DO THIS
public class UserService {

    private final UserRepository repo;

    public UserService(UserRepository repo) {
        this.repo = repo;
    }
}

Avoid using @Autowired on fields — it hides dependencies and complicates testing.

2. 🧼 Keep Controllers Thin, Services Fat

Why it matters: Controllers should delegate logic, not contain it.

// ❌ Don't mix HTTP logic with business logic
@GetMapping("/pay")
public String pay() {
    // payment + logging + validation logic = bad
}


// ✅ Delegate to a service layer
@GetMapping("/pay")
public String pay() {
    return paymentService.processPayment();
}

Follow proper Separation of Concerns (SoC).

3. 🧩 Use Profiles for Environment-Specific Configuration

Why it matters: Don't hardcode dev or prod values.

# application-dev.yml
server.port: 8080

# application-prod.yml
server.port: 80

Then activate via:

-Dspring.profiles.active=prod

Use profiles for toggling features, URLs, DBs, etc.

4. 🧪 Write Tests with @SpringBootTest + Mock Services

Use:

• @SpringBootTest for integration tests
• @WebMvcTest for controller layer
• @MockBean to isolate logic

Bonus: Use Testcontainers for realistic DB testing.

5. 📏 Limit What You Autowire

Avoid autowiring internal Spring beans you don't fully understand. Instead, write your own abstractions and expose only what your service needs.

Too much @Autowired = tight coupling.

6. 🐘 Use Flyway or Liquibase for DB Migrations

Manual SQL changes in production? Recipe for disaster.

Instead, use:

• Flyway: simple versioned SQL
• Liquibase: YAML/XML-driven migrations.

Ensure version control for schema changes.

7. 🐛 Handle Exceptions Globally

Use @ControllerAdvice and @ExceptionHandler to centralize error handling.

@ControllerAdvice
public class GlobalExceptionHandler {

@ExceptionHandler(NotFoundException.class)
    public ResponseEntity<String> handleNotFound(NotFoundException ex) {
        return ResponseEntity.status(404).body(ex.getMessage());
    }
}

✅ Consistent API errors ✅ Better logs ✅ Easier debugging

8. 🧹 Use DTOs to Avoid Entity Leaks

Don't expose JPA entities directly in controllers. Use DTOs (Data Transfer Objects).

Why?

• Prevent over-fetching
• Avoid LazyInitializationException
• Secure internal data (like passwords, IDs)

9. 🕵️‍♂️ Enable Actuator in Production (Carefully)

Spring Boot Actuator gives insight into health, metrics, env, logs:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-actuator</artifactId>
</dependency>

But be careful:

• Disable sensitive endpoints (/env, /beans) in prod
• Secure with auth

management.endpoints.web.exposure.include=health,inf

10. ⚙️ Externalize Configuration (Don't Hardcode Secrets)

Never hardcode secrets in application.yml

Use:

• Environment variables
• Vaults (like HashiCorp Vault, AWS Secrets Manager)
• .env files (with Spring Cloud Config or Dotenv libs)

Keep secrets out of source control.

11. 🔁 Enable Retry, Circuit Breaker, and Rate Limiting

If you're calling external APIs or DBs — expect failure.

Add resilience:

• @Retryable with Spring Retry
• @CircuitBreaker with Resilience4j
• Rate-limiting via Redis or Bucket4j

@Retryable(maxAttempts = 3)
public String callExternalApi() {
    // ...
}

12. 🧪 Monitor, Log and Trace Everything

Use production-grade tools:

• Micrometer (metrics)
• Prometheus + Grafana (monitoring)
• ELK Stack or Loki (logs)
• OpenTelemetry or Zipkin (distributed tracing)

Use structured logs (JSON) and add request IDs for correlation.

🧵 Conclusion

🧠 Final Thoughts

Spring Boot gives you the power to ship fast — but with great power comes great technical debt (if you're careless).

Follow these best practices, and you'll:

• Write maintainable code.
• Avoid painful bugs in prod.
• Earn the respect of your fellow devs (and your future self).