What is Kestrel?

Kestrel is a cross-platform, open-source web server designed for ASP.NET Core applications. It is the default web server included in ASP.NET Core project templates and is known for its high performance and efficient memory utilization. Here are some key points about Kestrel:

Key Features and Benefits

1. Cross-Platform Compatibility:

   • Kestrel can run on any platform supported by .NET Core, including Windows, Linux, and macOS[4][5].

2. High Performance:

   • Kestrel is designed to be lightweight and fast, making it suitable for high-performance applications. It is event-driven and uses asynchronous I/O operations, which contribute to its efficiency[3][4].

3. Integration with ASP.NET Core:

   • Kestrel is tightly integrated with ASP.NET Core, providing a consistent hosting environment. It is included by default in new ASP.NET Core projects and can be configured easily through code or configuration files[4][5][14].

4. Flexible Hosting Options:

   • Kestrel can be used as a standalone web server or behind a reverse proxy server like IIS, Nginx, or Apache. Using a reverse proxy is recommended for production environments to handle tasks like SSL termination, URL rewriting, and load balancing[3][5][8].

5. Configuration and Extensibility:

   • Kestrel offers various configuration options, such as setting limits on request sizes, connection timeouts, and more. These configurations can be set in the Program.cs file or through configuration files like appsettings.json[9][11][14].

6. Event-Driven Architecture:

   • Kestrel uses the libuv library, which is also used by Node.js, to handle I/O operations. This event-driven architecture allows Kestrel to efficiently manage multiple connections and provide high throughput[4].

Usage Scenarios

• Self-Hosting:

  • Kestrel can be used to host ASP.NET Core applications directly, making it suitable for scenarios where a lightweight, high-performance server is needed without the overhead of a full-featured web server[3][8].

• Behind a Reverse Proxy:

  • In production environments, Kestrel is often used behind a reverse proxy server. This setup allows the reverse proxy to handle incoming HTTP requests and forward them to Kestrel, which processes the requests and returns the responses[5][8].

Example Configuration

Here is an example of how to configure Kestrel in an ASP.NET Core appli...