It's not possible to upload a hidden file. 

Can you please share more details about your use case? Maybe, there is a workaround I can recommend. 

Hi,

I would like to upload a file so that the user can view a temporary embedded link of the file, but when the user returns to their files on Box, they cannot see the file. 

Is it possible to create the file, request the temporary view link, delete the file and still be able to view the embedded link? (Or if I opened the temporary embedded link and then deleted the file?)

Thank you!

You can set an expiration date for a shared link.

My use case is simply a need to migrate between system, and box is the company recommended temp storage solution. Suppose I want to copy a local .gitconfig file which overrides default git configurations. Now let that hiddent git file exist with a large number of other files which are both hidden and not hidden. Then, it becomes impractical to move such files via box. 

Current work-around is simply to add all files to a compressed archive (e.g. zip, tar, etc). Works for my needs, but still inconvenient.