Hi, @Vinod Kumar
Thanks for the reply.
Would it not be possible (at least for Google Drive); to simply let Google's file permissions handle it. e.g. Sharing a vault with my client I would need to first share the folder (Via Google Drive), then they can get their own OAuth token, and point the vault to the in their own drive account. (This would also mean that if I decided later to revoke access I could just remove their permissions on Google Drive).
With a little more code, it could be that Enpass verifies permission to the folder via the Drive API and gives the request access button if they don't.
Please, Please, Please reconsider this. I love the idea of Vaults, but simply can't use them as they are now.