AutoFac vs Simple Injector: What are the differences?

Key Differences between AutoFac and Simple Injector

1. Integration with .NET frameworks: AutoFac provides seamless integration with various .NET frameworks such as ASP.NET, ASP.NET Core, and many more. It offers specific integration packages that make it easier to work with these frameworks. On the other hand, Simple Injector focuses on providing a lightweight and fast dependency injection container, without providing specific integration packages for different frameworks.

2. Registration API design: AutoFac offers a more traditional registration API design, allowing you to register your dependencies using fluent syntax or attributes. It provides a wide range of registration options, including automatic type scanning, module-based registration, and more. Simple Injector, on the other hand, has a more explicit and deterministic registration API design. It encourages you to explicitly register your types and dependencies, avoiding any auto-wiring or implicit registrations.

3. Verification and diagnostics: AutoFac has a built-in mechanism for verifying your container configuration at runtime. It helps catch potential configuration errors and provides meaningful diagnostics messages. Simple Injector takes a different approach and focuses on preventing any invalid configurations at compile-time. It uses a static analysis tool to detect any potential misconfigurations during the build process, helping you catch them early.

4. Lifestyle options: AutoFac offers a wide range of lifestyle options, including transient, singleton, per-request, and many more. It also allows you to define your custom lifestyles if needed. Simple Injector provides a similar set of lifestyle options but with a focus on performance and deterministic disposal. It has a unique hybrid lifestyle called Scoped, which combines the benefits of transient and singleton lifestyles, providing controlled disposal and optimal performance.

5. Interception: AutoFac provides an interceptor mechanism that allows you to intercept and modify method calls on registered types. It supports both dynamic and compile-time interceptors. Simple Injector, on the other hand, does not provide built-in interception capabilities. Instead, it encourages you to use decorators to add cross-cutting concerns to your dependencies.

6. Community and support: AutoFac has a large and active community with extensive documentation, tutorials, and third-party integrations. It has been around for a long time and has established a strong reputation in the .NET ecosystem. Simple Injector, although smaller in terms of community size, has a very active and responsive support team. It also provides extensive documentation and has a focus on simplicity and performance.

In Summary, AutoFac and Simple Injector have their own unique features and design choices. AutoFac focuses more on integration with various .NET frameworks, while Simple Injector prioritizes simplicity, performance, and explicit configuration. The choice between them depends on your specific requirements and preferences.