There is a middle ground which all browsers do support, and not require permission prompts - Origin private file system https://developer.mozilla.org/en-US/docs

There is a middle ground which all browsers do support, and not require permission prompts - Origin private file system https://developer.mozilla.org/en-US/docs/Web/API/File_System_API/Origin_private_file_system https://developer.mozilla.org/en-US/docs/Web/API/File_System... If you're not familiar it's a file-system like API for writing files to an opaque non-user-accessable file system. Your application could probably provide it's own export functionality using blob urls, and import using traditional file "upload".