Summary: Contractor to develop solution that uses Twilio SMS service (or similar service, upon discussion) to authenticate that a phone number is associated with device using iPhone app.
Most importantly, this is NOT a complete app that you will be developing, simply a single function to be used for login. This is one of a series of functionality tests to be used to both support the development of a prototype, but also determine skilled/capable programmers who may be asked to participate in the development of a larger project in the future.
Estimated time to complete: 4 - 5 hours at most for a developer who has worked extensively with stackmob, twilio, objective-C, and core data following discussion with client via skype to answer any questions.
A successful engagement will result in a complete end-to-end function. A complete end-to-end function will include a simple (out of the box UI elements only - no "design") UIViewController interface developed in objective-C to ask for the user's phone number (properly formatted) and email (properly formatted as well), send a one-time use 4-character numeric password to the communication method of choice (via SMS or email). and once logged in will register user as being logged in using the isLoggedIn method as part of the Stackmob API (see below requirements.)
1) Server: Stackmob highly preferred; likely requires "custom code" module. If you do not have access to this, but have experience with it, please let me know.
2) SMS: Twilio preferred, but flexible if you have your reasons for recommending an alternative.
3) Email: Your choice of how to implement, lower cost options and free for low volume (testing volumes) preferred.