Thanks for this suggestion, Jeremy! I had forgotten about the callback method. However, after trying this, all of my recordings now seem to be empty. The zip files are saved to my server, but when I unzip them I get the following error (using the command line utility unzip on macOS: warning [uploads/ef29bba9-9e2c-3325-5b27-5ee7bff1179a.zip]: zipfile is empty Any idea why that might be the case?