Mobile phones have come a long way in terms of technological features, however, not all solutions need a mobile application or a web application. A simple USSD application will suffice in some cases.
USSD stands for Unstructured Supplementary Service Data. It is a GSM (Global System for Mobile Communications) protocol that is used to send text messages.
It involves a USSD code query sent from a mobile phone user, which produces a menu for the user to select the option they would like e.g. a request for a bank account balance. Upon receiving the user's request, the USSD gateway forwards it to the USSD application, which responds accordingly.