Hi there!
Do you intend on involving other cards than eye-fi (eg Transcend oder FlashAir)? eye-fi is not really the best solution to use with an DSLR... So, hopefully you will extend your app with more cards.
Transcend or FlashAir
Re: Transcend or FlashAir
Sorry, Eye-Fi is by far the most popular, primarily because it has the best range & device support. I don't have time to add other cards. I do intend to support more native (in-camera) wifi, later...