Cards, Code, and The App That Doesn’t Exist: The Magic Behind iPredict+

How do you build an app that doesn’t exist? That’s a question only a magician can answer and a problem only a hacker can solve, and the central question for Greg Rostrami, Randy Croucher and Hani Naguib, the team behind iPredict+.

iPredict+ is a fortune telling app used by magicians for card prediction tricks. If all goes according to plan, no one notices the magician ever used the app.

Here’s how it works: The magician asks his volunteer to pick a card. After the volunteer tells him what card they chose, the magician mentions a fortune teller who can predict the card they chose. He then asks the volunteer to call his “fortune teller.” They get the fortune teller’s voicemail which says, “Hi, sorry you reached my voicemail, but you called here for a reason. The card you picked is…” and the big reveal is dead on.

The iPredict+ app looks identical to your iPhone’s Contacts page, but has a planted contact–the fortune teller. Once the magician knows the card the volunteer selected, he taps the fortune tellers contact and enters a secret code which updates the Twilio Voice response to accurately predict the chosen card. The whole thing takes less than half a second, and looks like the magician just tapped his phone’s screen.

Veteran magician, Greg Rostrami, senior developer, Hani Naguib and iOS developer Randy Croucher wanted to create the “perfect trick” for magicians by making an invisible app.The perfect trick is one you can perform at anytime, anywhere, without the aid of props. Greg explains, “iPredict+ is like a utility device that is always with you that doesn’t look like a gimmick. It’s not a deck of cards, it’s not a prop and you don’t have to be a slight of hand master to be able to perform it. It’s just this very powerful hidden magical tool that’s always with you.”

App developers  ask Greg the secret behind the app, and programmers ask Hani for the code that instantly updates the TwiML paired to the fortune teller’s number. With the new iPredict+ recently launched new app features on the way, that’s one bit of magic they’re not ready to reveal.