Something I just posted on the Ruby on Rails mailing list, in response to sending SMS messages from a web application.

I rolled out SMS via a gateway provider. In my case, Simplewire.com, which does have a cost.

The reasons I chose a gateway provider:

I can’t count on the users providing detailed information, such as which network they are using. (12223334444@networkproviders.com). Also I am sending internationally in some cases.

My users wanted more detail on delivery. Which I can get using the gateway provider, saving the “ticket” and querying for confirmation with the gateway.

I considered using the e-mail method, where a user chooses their network. But with number portability hitting the US, it will cause too many issues down the road with users not updating their network settings.

Another option, which I have not tested thoroughly, is to piggy back on the AIM network, which can send SMS messages now. Though I am not certain what their policy is regarding automated use, and certainly any significant volume of messages will trigger a red flag.

The trick with SMS gateways is that you purchase a number of “credits”. Each message will cost 1 or more credits, depending on the network the message is destined for.

You can buy credits in bulk, for example Simplewire’s rates start at:

1,000 Message Credits for $57 USD 5.7 ¢ / Credit

10,000 Message Credits for $450 USD 4.5 ¢ / Credit

50,000 Message Credits for $2100 USD 4.2 ¢ / Credit

In the U.S., the credits per message range from 1 to 4 credits. I am negotiating for lower rates for an upcoming service, hoping to get the rate down to 2.5¢ per credit.

Another option is to setup your own gateway using something like Kannel.org or SMSTools. You then need to pay fees to connect to SMS network in some manner, direct, GSM modem or mobile phone.