Free SMS API in web application [closed]

Question

Most mobile providers support SNPP (Simple Network Paging Protocol). Despite the name, SNPP is also used to send text messages to cell phones. It's really easy to use. Just determine which mobile provider each user is using and then dispatch a "page" to the corresponding SNPP server.

For example, Sprint's SNPP server is snpp.messaging.sprint.com:444. The basic process goes like this:

1. Open a connection to the SNPP server.
2. Send PAGE The phone number
3. Check for status code 250 in the reply.
4. Send MESS Your message
5. Check for status code 250 in the reply.
6. Send SEND
7. Again, check for status code 250
8. Send QUIT

Some servers also support subject lines and delayed messages, along with two-way messaging.

I think you may have a problem here...

SMS's always end up costing someone, something... You may get lucky and find a provider that has a beta or test account that allows you to send out a handful, but they may not last that long.

I used to use a place that put a 20 character advert on the end of every message, but even they stopped.

Just did a quick google for you and could not come up with any... If you are more specific such as country, you may get better answers...

edit - Just seen someone else answering with a site that looks good! - My comment is based on the UK! I am still not aware of any free provider here.

They're not free, but without a doubt the best supplier I've worked with is Clickatell http://www.clickatell.com/

They're in over 200 countries, 800 networks and their pricing is quite reasonable. They support REST HTTP/S, SOAP HTTP, FTP, SMTP, SMPP. They also support premium rate messages and MMS to generate revenue.