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🧩 Service Lifetimes in Dependency Injection (.NET Core) – Explained with Analogies (Fresher Experienced Architect)

🎯 Introduction

In .NET Core’s built-in Dependency Injection (DI), services can have different lifetimes: Transient, Scoped, and Singleton.
Understanding these lifetimes is essential for writing efficient and bug-free applications.

👉 Full detailed article:
https://fullstackprep.dev/articles/webd/netcore/service-lifetimes-in-di-dotnet-core

🔗 Explore more .NET interview prep & guides:
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👶 Fresher Level: Analogy

Imagine you’re at a coffee shop:

Transient → You get a fresh coffee every time you order.

Scoped → You get one coffee cup to refill during your entire visit (one per request).

Singleton → The shop has a giant shared coffee pot that everyone uses.

Each lifetime has its purpose, just like how coffee is served differently depending on the situation.

👨‍💻 Experienced Level: Technical Breakdown

Transient

New instance every time it’s requested.

Lightweight, stateless services.

Scoped

One instance per HTTP request.

Useful for request-specific data (e.g., user session).

Singleton

Single instance for the entire application lifetime.

Good for configuration, logging, caching.

Example
services.AddTransient();
services.AddScoped();
services.AddSingleton();

👉 More examples explained here:
https://fullstackprep.dev/articles/webd/netcore/service-lifetimes-in-di-dotnet-core

🏗️ Architect Level: Enterprise Perspective

For architects, lifetimes affect:

Memory Management → Singleton reduces allocations but risks memory leaks.

Scalability → Scoped lifetimes ensure request isolation in multi-user apps.

Thread Safety → Singleton services must be thread-safe.

Design Patterns → Choosing the right lifetime aligns with SOLID principles and microservices design.

Bad lifetime choices can lead to performance issues, data leaks, or concurrency bugs.

🚀 Closing Thoughts

Service lifetimes in DI are like how coffee is served in a café:

Fresh every time (Transient),

One cup per visit (Scoped),

Shared pot for everyone (Singleton).

👉 Read the full deep dive here:
https://fullstackprep.dev/articles/webd/netcore/service-lifetimes-in-di-dotnet-core

🔗 Explore more .NET topics & interview prep:
https://fullstackprep.dev

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