How to Build an SMS Service

Using an SMS Aggregator

Using an SMS aggregator is the most traditional way to implement an SMS service SMS aggregators, or SMS brokers, have negotiated deals with all the major carriers to deliver SMS messages through a thick pipe directly to the SMS-Cs. In turn, the aggregators expose web interfaces to third parties that wish to send and receive SMS messages programmatically.

The Basics

Figure 3. SMS aggregator network architecture simplified

Figure 3 illustrates the basic set up. Your web service communicates with an SMS aggregator via SOAP, FTP, SMPP, or any number of other protocols. The aggregator, in turn, communicates with each individual carrier's SMS-C via SMPP to send and receive messages on your behalf.

There are many aggregators in business today and all offer slightly different sets of services, coverage, and pricing. We can't endorse or recommend any one service in particular, but we can describe two basic tiers of SMS aggregator on the market.

The first is intended for smaller companies that are either experimenting in SMS or operating at low volume (e.g., less than 100,000 messages). These services offer you the ability to pay by the message, usually by purchasing batches of credits. Clickatell is a well known example of a service in this category.

In the second category are companies such as mBlox, OpenMarket (which acquired SimpleWire), and Sybase 365. These companies ...