Different Ways to Manipulate Data Using DTOs (Data Transfer Objects)

In modern application architectures, Data Transfer Objects (DTOs) play a crucial role in shaping, validating, and transforming data between layers. DTOs are not just data containers—they are a strategic tool for clean architecture.

What is a DTO?

A DTO (Data Transfer Object) is a simple object used to move data across application boundaries such as APIs, services, or microservices without exposing internal domain models.

1. Data Shaping (Selective Field Exposure)

DTOs allow you to expose only the required fields to clients and hide sensitive data.

// Entity
User {
  id
  name
  email
  password
  role
}

// DTO
UserResponseDTO {
  id
  name
  email
}

2. Data Transformation

DTOs are ideal for transforming raw backend data into UI-friendly formats.

OrderDTO {
  orderId: string
  totalAmount: "₹1,250.00"
  orderDate: "06 Jan 2026"
}

Tip: Formatting data in DTOs keeps frontend logic simple and consistent.

3. Aggregation and Computed Fields

DTOs can introduce computed fields that do not exist in the database.

CartSummaryDTO {
  totalItems: number
  totalPrice: number
  discountApplied: boolean
}

4. Input Validation and Sanitization

Request DTOs validate and sanitize incoming data before it reaches business logic.

CreateUserDTO {
  name: string
  email: string
  age: number
}

5. API Versioning Using DTOs

Different DTOs can represent different API versions without touching core logic.

• UserV1DTO – Basic fields

• UserV2DTO – Profile + metadata

6. Performance Optimization

DTOs reduce payload size and database load by returning only summary data.

UserOrderSummaryDTO {
  userId
  totalOrders
  totalSpent
}

7. DTOs in Microservices

DTOs act as stable contracts between microservices, enabling loose coupling.

Best Practices

Practice	Recommendation
Expose Fields	Only what client needs
Validation	At DTO boundary
Versioning	Separate DTO per API version
Business Logic	Never inside DTOs

Conclusion

DTOs are a cornerstone of clean architecture. When used correctly, they improve security, performance, scalability, and maintainability of applications.

Mastering DTO-based data manipulation is essential for building production-grade APIs and microservices.