I am designing a grocery shopping app and I want to let the user to create account using name, email, mobile, password and can continue using the app using social media login. The mobile number is required because the delivery men contacts the customer when he reaches his location. Is it mandatory to ask the user to verify the mobile number to make sure that he owns the mobile number ?
Consider the customer's perspective. Say you don't verify the mobile number and the customer makes an order. In this age of rapid delivery, there's very little patience for mistakes or tardiness. When the delivery man tries to call but can't get through, the customer will think that your service is unreliable, not that they made a mistake and provided an incorrect number. You'll have lost a customer.
A principle of good design is to make it as easy as possible for a user to do what they want to do. In this case, what they want is error free recovery from a problematic delivery. Verifying their phone number gets you that fallback capability.
I'd say that while it's not technically mandatory, you'd be well advised to verify it, given that a valid phone number is necessary for delivery of groceries. You could even think about using something like Digits to handle the login rather than social media. That would take care of the account setup and phone verification all in one.
If the service is not possible without a phone number my suggestion is you require it and verify it. The verification could be done on sign up (no final step of account creation until verification) or after but always before using the service.
Not verifying the number could bring some problems:
- User entered a wrong number mistakenly.
- User entered a wrong number on purpose. For example, because he didn't know it was necessary for the service to be accomplished and didn't want to give that personal information.
So to avoid these possible problems I would require the verification.