Firebase Storage - update file while keeping same URL

You can update the file by uploading the new content to the same path, but you have to have a proper write permission set. This SO question might help: https://stackoverflow.com/questions/41423890/is-there-a-way-to-overwrite-a-saved-file-in-firebase-storage. Since firebase storage stores files on google cloud storage bucket you can manipulate files with its SDK as well which has richer set of functions if you need more control.