Programmatic SMS [closed]

What is the best way to programmatically send an SMS text message?

Are there any free Web Service based SMS gateways?

I know that if I happen to know the user's carrier (Sprint, AT&T, etc), I can send an SMS by emailing an address based on phone number + carrier. I would like a good solution that does not require me to know the carrier. Barring that, is there an easy way to lookup carrier given a cell phone number?

I understand that there are some services independent of the major mobile carriers that offer a per-message fee-based service, with API. What I would like to know is how such organizations tap into the SMS networks. Do they have contracts with mobile carriers to resell their services?

Solution 1:

Use http://www.twilio.com/

They have a REST interface to send SMS's and even to establish phone calls or receive phone calls.

You even get 30$ credits to try it out.

Def. the cheapest solution you will find.

Solution 2:

Where I work we've been using http://www.clickatell.com for sending out SMS - it looks like its about 6 or 7 cents a message. They just take http POST requests to send out a message. I don't know if you'll be able to find any good free gateways. We used to send out emails, but found they were unreliable.