I also thought of trying to make a custom transaction type so that I could use render.transaction and set the printMode to HTML. Both of these approaches feel a bit hacky. Not sure which one is worse.

I think I have done something similar following this approach:

var renderer = render.create();

renderer.templateContent = file.load({ id: ScriptVariables.TemplateID }).getContents();

renderer.addCustomDataSource({

alias: 'some_name_variable',

format: render.DataSource.OBJECT,

data: object_with_values_expected_on_template

});

I created my own HTML file using the Advanced PDF syntax, uploaded to the file cabinet, then I passed the data expected using the

.addCustomDataSource

It will work similar to handlebar or other template libraries You can then do:

renderer.renderAsPdf()

and create a file or whatever you need with the content.

Yes that is essentially what I want to do, the problem is I need the output to be HTML, not PDF, since I am using it for the body of an email message. Sadly, there is no renderAsHtml function.