How to Build an SMS Service

Types of SMS Service

In some ways, SMS is just an input/output protocol for an application. A quick survey of existing applications can help frame what types of requirements your service may generate. While this list is far from exhaustive, it is useful to recognize five basic categories, which we'll explore in the following sections: notification, lookup, messaging and social networking, action and what we call, for want of a better term, art.

Notification

Notification is the simplest type of SMS service: you sign-up to receive a message on your phone when some event occurs (i.e., not in response to a proximal user action). For example:

• Microsoft's Windows Live Alerts sends stock quotes, traffic updates, horoscopes, and more via SMS.

• Google's Calendar service sends reminders for events via SMS.

• University of Amsterdam sends students their exam results via SMS.

While these types of services tend to be "set and forget," they can also be interactive. While there is no response required when receiving a weather report via SMS, but a stock quote received via SMS could engender a "sell" reply and a resulting action on your behalf.

Notification services tend to be the easiest to create. As we will show in later sections, any of the implementations of SMS service will lend itself to a notification service.

Lookup

In a lookup service, the user initiates the SMS conversation. For example:

• Send "Define <word>" to 46645 (GOOGL) or 95482 (WLIVE) and you will receive an SMS response with the word's definition. ...