After doing a bit of research I found out about the AWS S3 bucket and the simple-file-upload Simple File Upload | Heroku Dev Center (which on the user interface part sounds the same as the dcc.Upload that @Emil mentioned?). I’m struggling to understand if this feature is free or not, because the linked webpage errors out.
Also, is the simple-file-upload the ‘back-end’ part of the dcc.Upload component? Can I use dcc.Upload without setting up the simple-file-upload / AWS S3 bucket ? Then where would the uploaded file be stored? Will I have to re-push the entire app for the effect to take place?