# 🚀 Building Microservices with Ease

This content originally appeared on DEV Community and was authored by SOVANNARO

A Happy Guide to Using DTOs and REST APIs in Spring Boot

In the exciting world of software development, building powerful, flexible, and scalable applications is a dream many developers share. One of the most effective ways to achieve that dream? Microservices. And guess what? You don’t need to be a wizard to build them. With the help of DTOs (Data Transfer Objects) and REST APIs, you can structure your app like a pro—and have fun doing it!

Let’s walk through the journey together—from the basics of DTOs to building your first RESTful microservices using Spring Boot.

What’s a DTO and Why Should You Care?

Imagine you’re delivering a package to a friend. You wouldn’t just throw in random things, right? You’d pack exactly what your friend needs—neatly and securely. That’s what a Data Transfer Object (DTO) does.

A DTO is a simple class that only holds data. No business rules, no logic—just pure, clean information. It helps you move data between different parts of your application without exposing too much or making a mess.

Why DTOs Make Life Easier

• Less Network Traffic: You can send just what’s needed, all bundled nicely in one object.
• Cleaner Code: It separates your data from business logic, making your app easier to manage.
• Loose Coupling: Your layers stay independent. Want to change how data is shown? No worries—you won’t break the backend.

A Quick DTO Example

Let’s say we have a CustomerDetailsDTO that holds customer info:

public class CustomerDetailsDTO {
    private String name;
    private String email;
    private String mobileNum;

    // Getters and Setters
}

You can use this DTO to transfer data between your frontend and backend (or even between microservices). With the help of a mapper, this DTO can be converted into a database entity—and vice versa—without breaking a sweat.

Let’s Build Microservices (Step by Step)

Ready to build something amazing? Here’s a simple roadmap to get you from zero to a working microservices system using Spring Boot.

Step 1: Create Empty Spring Boot Apps

Start with creating Spring Boot projects. Add dependencies like:

• Web
• Spring Boot DevTools
• JPA
• H2 DB (for in-memory testing)
• Lombok
• Spring Doc (for API documentation)

This is your microservices playground—clean and ready to build on!

Step 2: Build Database Logic and DTOs

• Set up your database tables and entities using JPA.
• Use DTOs to define what data moves in and out.
• Write mappers to convert between DTOs and entities. You can use tools like MapStruct or write them manually.

Step 3: Add Business Logic with REST APIs

Use annotations like:

• @PostMapping – to create data
• @GetMapping – to read data
• @PutMapping – to update data
• @DeleteMapping – to delete data

These become the building blocks of your microservice’s brain!

Step 4: Handle Errors Gracefully

Use:

• @ControllerAdvice to create a global error handler
• @ExceptionHandler to catch specific exceptions

You can even create custom exceptions like CustomerAlreadyExistsException to show friendly messages when something goes wrong.

Step 5: Validate Input Like a Pro

Before accepting any data, make sure it’s clean!

Use Jakarta Bean Validation annotations:

• @NotEmpty
• @Size
• @Email
• @Pattern
• @Valid or @Validated

This keeps your system safe from bad data.

Step 6: Add Auditing with Spring Data JPA

Want to know who created or updated data and when?

Add audit fields like:

@CreatedDate
@CreatedBy
@LastModifiedDate
@LastModifiedBy

Enable auditing using @EnableJpaAuditing and Spring will track it all for you—automagically!

Step 7: Document Your APIs with Swagger & OpenAPI

Use annotations like:

• @Tag and @Operation – to describe your API
• @ApiResponse – to define different response types
• @Schema – to explain your DTOs

With SpringDoc + Swagger UI, your REST APIs get a beautiful web interface for testing and learning.

Helpful Annotations & Tools You’ll Use

Wrapping Up

Microservices might sound scary at first, but once you break them down, they’re just a bunch of small, smart services working together—like a team of superheroes!

With DTOs, REST APIs, and Spring Boot, you can create clean, fast, and scalable applications. Whether you’re building for a startup or your next personal project, this pattern will help you write code that’s powerful and easy to maintain.

So go ahead—build something amazing. And most importantly, have fun while doing it!

This content originally appeared on DEV Community and was authored by SOVANNARO