Small shops that take bank transfers usually confirm them by hand: the bank app shows "deposit received", someone opens the order list and marks the order paid. Banks do offer APIs for this, but they come with contracts and fees that a small shop doesn't want. The phone already gets the information for free, as a notification. So I wired the notification straight into code. The setup I used Droidline, an open source tool I've been building. It has two parts: an Android ap...