SOLID & Design Patterns Interview Question #31

When should you use the Builder Pattern instead of a constructor?

Structural, Creational & Behavioral Patterns Junior Beginner

Quick Interview Answer

Use a builder when construction has many optional parameters, requires a meaningful sequence of steps, or benefits from a fluent domain-specific API. It can also centralize validation before the final object is created.

Detailed Explanation

For a small immutable type with a few required values, a constructor or record is usually simpler. A builder should reduce complexity rather than merely add another layer.

Code Example

public record ConnectionOptions(
    string Host,
    int Port,
    bool UseSsl);

// A simple type like this may not need a builder.