Dependency Injection AddScoped vs AddTransient in .NET Core

AddScoped vs AddTransient in .NET Core

When building applications with .NET Core, the dependency injection (DI) container is essential for managing object lifetimes. The AddScoped and AddTransient methods define different service lifetimes, and understanding their differences is crucial for optimizing performance and resource usage. In this blog post, we’ll compare these two lifetimes in a clear, tabular format.

Comparison Table: AddScoped vs AddTransient

Feature	AddScoped	AddTransient
Lifetime	Service is created once per request (or scope).	Service is created each time it is requested.
Use Case	Best suited for stateful or request-specific operations.	Ideal for lightweight, stateless operations.
Instance Sharing	The same instance is shared across components within the same request.	Each component gets its own new instance.
Performance	Moderate performance cost since one instance is reused per request.	Higher performance cost due to frequent object creation.
Example Scenario	Database context or user-specific data during a web request.	Utility classes like helper functions or mappers.
Memory Usage	Optimized for memory as fewer instances are created per request.	Higher memory usage due to multiple instances being created.

Key Points to Consider

Choosing between AddScoped and AddTransient depends on your application’s needs. Here are some guidelines:

• Use AddScoped when the service should maintain state across a single request or operation.
• Use AddTransient for lightweight and stateless services where a new instance is required for each use.
• Evaluate performance and memory trade-offs when deciding which lifetime to use.

Note: Mixing service lifetimes can lead to unexpected behaviors. For example, injecting a scoped service into a singleton service is not recommended and can cause runtime issues.

Conclusion

Understanding the differences between AddScoped and AddTransient is critical for building efficient, scalable, and maintainable .NET Core applications. By selecting the appropriate service lifetime based on your specific requirements, you can ensure optimal resource management and application performance.