How do you authorize SMS delivery?

I'm looking for the best practice, proper and "mobile carrier accepted" way of authorizing the sending of SMS/text messages to a cell phone number so that it can't be flagged as spam or abuse.

Basically, I want the user to enter in their cell phone number in my web app and then I want my web application to send some kind of SMS to them asking them to do som开发者_高级运维ething that tells the carrier and my app that they accept SMS messages from my web service. I do not want to spam - I only want people that want to receive the messages to their phone.

Also, I'm assuming that I can just SMTP to "email" text messages to their phone as well. Hopefully there's not a caveat to this method.

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I have a little experience in this area and AFAIK there is no 'opt-in' list. However, carriers typically use the keyword DELETE to allow users to block messages.

Most carriers support a SMTP gateway addresses but you will need to know the carrier for each number. Here's a list to get you started. Also most messages received via a SMTP gateway will appear to come from different numbers on the users phone. (This is annoying for iPhone users who are accustomed to grouping of messages by individuals.)

If you are willing to pay per message services like EZTexting can take away some of the pain by doing the carrier lookup for you or sending your message via a direct, and more expensive, SMS gateway.

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Here is a good overview :

http://www.acma.gov.au/webwr/consumer_info/frequently_asked_questions/spam_business_practical_guide.pdf

The US is actually behind with SMS regulations. We typically adhere to EU and Australian Legislation, which are stricter. The US will get there.

From a technical perspective:

You can use our Red API, just log on to www.redoxygen.com and select developers.