Are there any sites that offer the ability to send SMS for free?
How do they do it?
How am I able to send SMS programmatically?
Send an email to the 10 digit phone number @ Carrier's domain name.
Here is a list of the carriers and their domains:
The articles listed below may be useful:
Are there any free services for sending SMS programmatically?
[Programmatic SMS] [3]
[Free SMS API?] [4]
EDIT Removed first link that has been removed
I use an SMS gateway and it is fairly easy but I did consider this as an alternative because it potentially gave me more control email to sms
The sites that send SMS for free usually use the email interface that most of the carriers implement which allow you to send an email to (for instance) <your 10 digit number>@mobile.att.net
and have it received as an SMS by that phone.
来源：https://stackoverflow.com/questions/1061752/how-to-send-sms-programmatically