DTO

A Data Transfer Object (DTO) is a design pattern used to transfer data between layers in a software application. It is a plain object that contains data but no business logic. DTOs are commonly used in APIs, microservices, and database interactions to improve performance, security, and maintainability.

Features:

• Encapsulates Data: Contains only attributes (no behavior).
• Prevents Unnecessary Data Exposure: Restricts data transfer to only relevant fields.
• Improves Performance: Reduces serialization/deserialization overhead.
• Ensures Data Consistency: Avoids exposing internal models directly.

Why use it?

• Separation of Concerns: Decouples internal models from external data representation.
• Better Security: Prevents exposing sensitive fields (e.g., passwords).
• Improved Performance: Reduces data transferred over the network.
• Easier Versioning: API responses remain stable even when internal models change.

Examples

DTO in Python (Using Pydantic for API Data Validation)

from pydantic import BaseModel
 
class UserDTO(BaseModel):
    id: int
    name: str
    email: str
 
def get_user() -> UserDTO:
    return UserDTO(id=1, name="Alice", email="alice@example.com")

Prevents unnecessary fields (e.g., passwords) from being exposed in API responses.

DTO in Java (Using Lombok for Simplicity)

import lombok.Data;
 
@Data
public class UserDTO {
    private int id;
    private String name;
    private String email;
}