What is short code?
Short codes, or short numbers, are short digit sequences, significantly shorter than telephone numbers, that are used to address messages short message service (SMS) systems of mobile network operators.
Short codes are widely used for value-added services such as charity donations, mobile services, ordering ringtones, and television program voting. Messages sent to a short code can be billed at a higher rate than a standard SMS and may even subscribe a customer to a recurring monthly service that will be added to the customer's mobile phone bill until the user texts, for example, the word "STOP" to terminate the service.