You can accept multiple files for upload, by using the multiple property of the FileLoader component! You’ll then get a list of media object as self.file_loader_1.files, which you can loop over and upload one by one, by passing them to a Server Function. (@stefano.menci is right – you’ll want to make a separate server call for each to avoid timeouts.)
Here’s a simple example app that uploads multiple files, and shows progress:
https://anvil.works/build#clone:5FLJ75BOJ4RZ3ONA=SLJRBULUYKKROCIIGOI2H4FA
And here it is in action:
