SMS verification for mobile apps

Currently, one of the most important uses of SMS messaging is SMS verification for mobile apps.

SMS verification consists of sending an SMS with a unique code that the user has to enter within a mobile app to validate their mobile phone number. This functions allows apps to make sure that the phone number stated belongs to the user.

At the moment, no other method or technology exists that can carry out this validation as easily. Mobile apps are in constant communication via the internet, but this connection isn’t able to validate one principal piece of information about the user: their mobile phone number.

An SMS travels through the GSM network and is received by a specific SIM which has a unique mobile phone number. This characteristic means that that the SMS is a perfect symbol to send one-time codes or passwords (OTPs).

Examples of use of SMS verification.

Initial association: many apps require the user’s phone number to be validated just after installation, and often, validating the user’s phone number is necessary for using the application. Messaging apps (such as WhatsApp, Line, Telegram, WeChat etc.) or social networks (Facebook, LinkedIn etc.) use these services to validate and identify their users.

Secure access: other apps require the introduction of an SMS code to access actions or restricted screens. Many of these applications are related to transactions of money such as access to online banking (HSBC, JP Morgan, Deutsche Bank, Barclays, Citigroup etc.) or companies for making payments online (Stripe, PayPal, 2Checkout etc.).

Alternative methods

Sending SMS verification to validate users is the most efficient and direct method, but it isn’t the only one that exists. We present below several methods which applications use to validate or identify their users:

1.    Telephone calls. Through automatic calls with IVR systems, call centers or similar, users receive instructions on how to validate their account, for example, entering a code which they see on the screen. This system functions well if the user picks up the call or if it is the user that has to call a phone number.

2.    Sending an SMS. This system consists of sending SMS messages to a special number which receives and processes SMS. This message contains a number of origin which will be validated and linked to the user.

3.    Fingerprint. Nowadays, a number of devices contain a fingerprint detector and operating systems offer functions to identify the user using this tool. This system is ideal for verifying actions or transactions, since it verifies not just the number but also the user that is using the device. However, this method cannot validate the phone number associated with the user’s account.

4.    Email. Users can also validate themselves sending an email with specific content. However, this method only validates their email address and not their mobile phone number.