I would like to create a budget app for Android. Obviously, to be competitive, I would need to allow users to get data from their bank. For [huge] security reasons, this stuff is not just freely given to any would be developer, but I know it can be done. There are budget apps that connected to users banks.
My question is, what do I need to do to poll users bank data? Do I need to contact every bank that I wish my app to deal with? Do I need to write the app and present it the the bank(s)? Or am I just too ignorant to take on a challenge of this magnitude?
I ask because I obviously don't know the standards that are needed here and would like to learn about them, even if it ends up that I cannot write the bank interface section of my app.