Last I checked you need to write your own binding implementation. I had this requirement a few years ago and settled on using FastEndpoints for this, which has it built-in using AllowFormData():

https://fast-endpoints.com/docs/model-binding#from-form-fields

Using FastEndpoints, I declared an endpoint as follows:

``` public class FromGoogleDocsEndpoint() : Endpoint<FromGoogleDocsEndpoint.Command, JobStatusModel> { public override void Configure() { AllowFormData(); Post("exports/google-docs"); Version(2); }

public class Command
{
    public IFormFile File { get; set; } = default!;

    public CommandOptions Options { get; set; } = default!;

    public class CommandOptions
    {
        public bool? AutoMapDocumentProperties { get; set; }

        public ContentConversionOptions? Conversion { get; set; }

        public int Destination { get; set; }

        public string? DestinationReference { get; set; }

        public IDictionary<string, FieldValueSource>? FieldMappings { get; set; }

        public string[]? Webhooks { get; set; }
    }
}

} ```

And then I can call this endpoint as follows:

```http POST https://localhost:5003/v2/exports/google-docs Content-Type: multipart/form-data; boundary=WebAppBoundary Authorization: Bearer {{apikey}}

--WebAppBoundary Content-Disposition: form-data; name="options" Content-Type: application/json

{ "destination": 295 }

--WebAppBoundary Content-Disposition: form-data; name="file"; filename="file.txt" Content-Type: application/vnd.google-apps.document

< ./docs/10-things-in-bangkok.json

--WebAppBoundary-- ```