Numbers can be opted into the TextPower system using multiple methods (see the FAQ HERE). In some specific instances messages can be sent to numbers that are not opted in. For example, the use of AlertDispatcher to send and receive messages from internal staff in the form of a two-way text messaging "chat" does not require numbers to be opted in.
Using the API call GetAccountData will return one of three different opt-in status indications:
- No Opt-In - The number is not opted in and can receive messages under certain special circumstances.
- Single Opt-in - This is the most common type of opt-in and is used in 99.9% of the configurations on the TextPower system. It means that a number has been uploaded to the system or has requested being subscribed to the messages for that keyword by sending a text containing the keyword to the TextPower system. No confirmation is required; a keyword is sent and the system responds with a confirmation that the number has been added.
- Double Opt-in - This type of opt-in was required at one time by specific carriers. It is no longer used but some numbers in the TextPower system may have been opted in this way in the past and thus may return this status when queried. A double opt-in requires a confirmation from the mobile user after the initial opt-in. The mobile user would text the keyword, receive a confirmation including a request to respond to the confirmation affirming that they agree to opt-in. Without the secondary affirmation (the "double" part of the "double opt-in") the opt-in would not be completed and the number not added to the opt-in list.
In the vast majority of cases accounts using a standard TextPower configuration, which typically includes a keyword (other than for AlertDispatcher as noted above), will use only the single opt-in process as described in 2., above.