Have you used Swagger for API documentation and testing?

Yes, Swagger is a popular tool for documenting and testing REST APIs. It allows for automatic generation of interactive documentation based on annotations in the code or OpenAPI specifications. In C#, the Swashbuckle library is often used, which integrates with ASP.NET Core and generates Swagger UI.

Example of integrating Swagger in ASP.NET Core:

public void ConfigureServices(IServiceCollection services)
{
    services.AddControllers();
    services.AddSwaggerGen();
}

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    app.UseSwagger();
    app.UseSwaggerUI(c =>
    {
        c.SwaggerEndpoint("/swagger/v1/swagger.json", "My API V1");
    });

    app.UseRouting();
    app.UseEndpoints(endpoints =>
    {
        endpoints.MapControllers();
    });
}

This allows developers and testers to quickly see the API description and make requests directly from the browser.