TextBelt is an outgoing SMS API that uses carrier-specific gateways to deliver your text messages for free. This is nice for a low-cost texting app or testing without running down your Twilio balance.
Usage is dead simple:
$ curl http://textbelt.com/text \
-d number=5551234567 \
-d "message=I sent this message for free with textbelt.com"
Sample success:
{"success":true}
Sample failure:
{"success":false,"message":"Exceeded quota for this phone number."}
IP addresses are limited to 75 texts per day. Phone numbers are limited to 3 texts every 3 minutes. To report abuse or request increased limits, please contact iwmiscs+textbelt at gmail.
Some carriers may deliver text messages from "txt@textbelt.com"
We support the following U.S. providers: Alltel, Ameritech, AT&T Wireless, Boost, CellularOne, Cingular, Sprint PCS, Telus Mobility, T-Mobile, Metro PCS, Nextel, O2, Orange, Qwest, Rogers Wireless, US Cellular, Verizon, Virgin Mobile.