Post
Ask Question

Differences Between Scoped, Transient, And Singleton Service

Introduction

In this article, we will see the difference between AddScoped vs AddTransient vs AddSingleton in .net core.

Why we require

  • It defines the lifetime of object creation or a registration in the .net core with the help of Dependency Injection.
  • The DI Container has to decide whether to return a new object of the service or consume an existing instance.
  • The lifetime of the Service depends on how we instantiate the dependency.
  • We define the lifetime when we register the service.

Three types of lifetime and registration options

  1. Scoped
  2. Transient
  3. Singleton

Scoped

  • In this service, with every HTTP request, we get a new instance.
  • The same instance is provided for the entire scope of that request.
    • eg., if we have a couple of parameter in the controller, both object contains the same instance across the request
  • This is a better option when you want to maintain a state within a request.
services.AddScoped<IAuthService,AuthService>();

Transient

  • A new service instance is created for each object in the HTTP request.
  • This is a good approach for the multithreading approach because both objects are independent of one another.
  • The instance is created every time they will use more memory and resources and can have a negative impact on performance
  • Utilize for the lightweight service with little or no state.
services.AddTransient<ICronJobService,CronJobService>();

Singleton

  • Only one service instance was created throughout the lifetime.
  • Reused the same instance in future, wherever the service is required
  • Since it's a single lifetime service creation, memory leaks in these services will build up over time.
  • Also, it has memory efficient as they are created once reused everywhere.
services.AddSingleton<ILoggingService, LoggingService>();

When to use which Service

Singleton approach => We can use this for logging service, feature flag(to on and off module while deployment), and email service

Scoped approach => This is a better option when you want to maintain a state within a request.

Transient approach =>  Use this approach for the lightweight service with little or no state.

What do you think?

I hope you enjoyed this article. I would like to have feedback from my readers.

Your valuable feedback, questions, or comments about this article are always welcome.


Similar Articles