Link Registration process with Login process

User experience wanted: Registration of a new account: User clicks on “Continue with Facebook”, logs into Facebook using his password, gets registered and Logged in at the same time. User can then use the app like normal. Here is how to do it (please remember, I am only talking about Facebook login) Registration and Login are two different processes due to a missing feature in our backend that is not solvable. That means that the user needs to register via a URL inside the webview, while the Login (which we need for getting the UserID) is done via an API call. I would like to combine them now. Here is how we can do it: After registration URL has been launched, the user will enter his login details into Facebook (as usual). Facebook will then validate it, and send the information to my server directly. Once the server has created the account, it will redirect to a URL with the string “?app-first-login-95658956976455-9786967078”. Once the app recognises this string, it needs to launch automatically the LOGIN procedure (which will then plant cookies, as usual). IMPORTANT: The user is not supposed to realise any of this. He should just see a pop-up with “We are creating your account right now” during the time that it takes from the redirection to the *.[login to view URL] (which signals that Facebook has validated the login) until Login procedure is completed. The app is a mixed app between webview 90% and 10% native iOS app. There is nothing to do in backend, just a combination of two working processes. The trigger is the Query string in the URL. Link to the existing app: [login to view URL]