Kestrel Web Server Vs Iis


The world of web servers is constantly evolving, with new technologies and solutions emerging to cater to the ever-increasing demands of web applications. In this article, we will compare two popular web servers, Kestrel and IIS (Internet Information Services), and explore their similarities, differences, and use cases.

What is Kestrel?

Kestrel is a cross-platform web server developed by Microsoft and built on top of the .NET Core framework. It is lightweight, fast, and designed to handle high loads efficiently. Kestrel is known for its ability to scale well under heavy traffic and is often used in combination with other web servers like IIS or Nginx.

What is IIS?

IIS, on the other hand, is a full-featured web server developed by Microsoft and primarily designed for Windows operating systems. It has been around for many years and is widely used in enterprise environments. IIS offers a rich set of features and tools for managing and hosting web applications, making it a popular choice for organizations.

Performance and Scalability

When it comes to performance and scalability, both Kestrel and IIS have their strengths. Kestrel is known for its high-performance capabilities, especially when used in conjunction with the .NET Core framework. It is optimized for handling a large number of concurrent connections and can efficiently process requests. However, Kestrel is primarily designed as an edge server and may not be the best choice for handling heavy workloads on its own. IIS, on the other hand, has been optimized for Windows operating systems and can handle a wide range of workloads efficiently. It offers features like application pools, caching, and load balancing, making it a robust choice for hosting large-scale web applications. IIS also integrates well with other Microsoft technologies like ASP.NET and SQL Server, providing a seamless development and deployment experience.

Flexibility and Portability

One of the key advantages of Kestrel is its cross-platform compatibility. Being built on .NET Core, it can run on Windows, macOS, and Linux, providing flexibility in deployment options. This makes Kestrel a great choice for developers who prefer working in a multi-platform environment or want to leverage the benefits of containerization technologies like Docker. IIS, on the other hand, is tightly integrated with Windows operating systems and is primarily designed for Windows Server environments. While it offers excellent support for Windows-specific features and technologies, it may not be the ideal choice for organizations that require portability across different platforms.


Both Kestrel and IIS offer robust security features to protect web applications from various threats. Kestrel supports TLS encryption out of the box and provides options for configuring HTTPS and enforcing secure connections. It also integrates well with authentication and authorization mechanisms provided by the .NET Core framework. IIS, on the other hand, offers a wide range of security features, including support for SSL/TLS, request filtering, and IP address restrictions. It also provides integration with Windows authentication and authorization mechanisms, making it a popular choice for organizations that require comprehensive security measures.

Development and Deployment

Kestrel, being a part of the .NET Core ecosystem, offers a streamlined development and deployment experience for developers. It integrates well with popular development tools like Visual Studio and provides built-in support for frameworks like ASP.NET Core. Kestrel also supports self-contained deployments, allowing applications to be deployed with all their dependencies bundled together. IIS, on the other hand, offers a wide range of tools and features for managing and hosting web applications. It integrates well with Microsoft development tools and provides a graphical interface for configuring and managing websites. IIS also supports traditional deployment methods like copying files directly to the server or using web deployment packages.

Use Cases

The choice between Kestrel and IIS depends on various factors, including the specific requirements of the application and the target environment. Kestrel is well-suited for scenarios where high performance and scalability are crucial, especially when combined with other web servers like Nginx as a reverse proxy. It is a great choice for modern, cross-platform applications that require flexibility and portability. IIS, on the other hand, is a robust choice for organizations that rely heavily on Windows technologies and require a full-featured web server with comprehensive management and security capabilities. It is particularly well-suited for enterprise environments that need to host large-scale web applications with complex configurations.


In conclusion, both Kestrel and IIS are powerful web servers with their own strengths and use cases. Kestrel excels in terms of performance, scalability, and cross-platform compatibility, making it a great choice for modern applications. On the other hand, IIS offers a comprehensive set of features and tools, making it an ideal choice for Windows-centric environments. Ultimately, the choice between the two depends on the specific requirements of the application and the target environment.