In ASP.NET Core Web API, URL rewriting can be achieved using the Microsoft.AspNetCore.Rewrite middleware. This middleware allows you to modify the request URL based on predefined rules. Here's how you can perform URL rewriting in ASP.NET Core Web API:

1. First, install the Microsoft.AspNetCore.Rewrite package from NuGet. You can do this by running the following command in the Package Manager Console:

   Install-Package Microsoft.AspNetCore.Rewrite 

1. In your Startup.cs file, add the following code to the Configure method:

   using Microsoft.AspNetCore.Rewrite;     public void Configure(IApplicationBuilder app, IWebHostEnvironment env)    {        // Other middleware configurations...         // URL rewriting        var options = new RewriteOptions();        options.AddRedirect("^api/oldendpoint$", "api/newendpoint");        app.UseRewriter(options);         // Other middleware configurations...    } 

In this example, the code is adding a redirect rule that will redirect requests from /api/oldendpoint to /api/newendpoint.

You can define more complex rules using regular expressions or create custom rewrite rules using RewriteRule or RewriteContext.

1. Save the changes and run your ASP.NET Core Web API application. The URL rewriting will now be in effect, and requests to the old endpoint will be redirected to the new endpoint.

Please note that URL rewriting should be used with caution as it can affect the overall behavior of your API. It's recommended to thoroughly test your rules and consider the impact on client applications and SEO.