NSwag and multiple api versions

Consider controllers below:

namespace Web.Controllers
{
    [ApiVersioning("1.0")
    [Route("api/v{version:apiVersion}/[controller]")]
    public class Product : ApiController
    {
        [HttpGet("id")]
        public IHttpActionResult<bool> GetProduct(Guid id) 
        { /* rest of the code */ }
    }
}

namespace Web.Controllers
{
    [ApiVersioning("2.0")
    [Route("api/v{version:apiVersion}/[controller]")]
    public class Product2 : ApiController
    {
        [HttpGet("id")]
        public IHttpActionResult<bool> GetProduct(Guid id) 
        { /* rest of the code */ }
    }
}

And Swagger documents in Startup class:

services.AddSwaggerDocument(config =>
{
    config.DocumentName = "v1.0";
    config.PostProcess = document =>
    {
        document.Info.Version = "v1.0";
    };
});

services.AddSwaggerDocument(config =>
{
    config.DocumentName = "v2.0";
    config.PostProcess = document =>
    {
        document.Info.Version = "v2.0";
    };
});

Now after testing the API browser with NSwag it ignores the versions and shows all the APIs in both v1 and v2 document.

How to tell NSwag to separate them?

I think you are missing ApiGroupNames property which is used to select Api version. Please add ApiGroupNames property like below code and let us know.

services.AddSwaggerDocument(config =>
{
    config.DocumentName = "v1.0";
    config.PostProcess = document =>
    {
        document.Info.Version = "v1.0";
    };
    config.ApiGroupNames = new[] { "1.0" };
});

services.AddSwaggerDocument(config =>
{
    config.DocumentName = "v2.0";
    config.PostProcess = document =>
    {
        document.Info.Version = "v2.0";
    };
    config.ApiGroupNames = new[] { "2.0" };
});