People use their phones 24/7 and don’t want to separate even for a second. Research by Pew Research Center has revealed that 85% of young adults in the US own a smartphone. The big trend of mobile phones has transformed the traditional way businesses did their marketing. With more technological advancement, a new marketing channel has evolved which is known as geofencing. Essentially this is a virtual fence around a geographical area defined in advance, and once a user enters this area, it triggers an action. Chances are, you have already heard about this but haven't realised it yet. This is because despite it’s relatively recent popularity as a marketing tool, geofencing has been around for much longer than you would imagine. Earlier systems used to be quite expensive and were mostly used in livestock industries to track herds of cattle through GPS, and when the herd left the predefined zone, the farmers would get an alert from the system. Now, geofencing has evolved into a unique marketing tool for industries way beyond livestock. In this article, we will learn about SMS geofencing and answer the most important question: how does SMS geofencing work?