How to Build an SMS Service

SMS Short Codes

A short code is a five or six digit (in the U.S.) phone number that is used to address SMS and MMS messages from a mobile phone. They are typically used because they are easier to remember than 10-digit or longer phone numbers.

When initially introduced, short codes were unique to each carrier (so the same short code might be owned by different application providers on T-Mobile and on Cingular, for example). However, in 2003, cross-carrier short codes were introduced in the U.S., and the ability to offer a single number accessible to all users, regardless of carrier, became practical.

In the United States, short codes are registered by a Common Short Code Administration, the Cellular Telecommunications & Internet Association. The application process for short codes is straightforward and can be completed quickly and easily at the CTIA web site, www.usshortcodes.com.

As of April 2007, pricing for short codes in the U.S. was as follows:

• Randomly assigned 5- or 6-digit code: $500/month

• Custom chosen 5- or 6-digit code: $1,000/month

Note, though, that short codes must be leased in three-month blocks of time and paid for upfront, so your initial payment for turning on a short code will be $1,500 to $3,000.

The fee, however, merely gives you the right to use the short code, but does not provide connectivity to the carrier. For that, you must go through an SMS aggregator service (see the "Using an SMS Aggregator" section later in this tutorial), where you'll end up paying for ...