The recipient of a sent message can reply back to the text message, if the message is sent to either the sms.textapp.net or sms160.textapp.net domains.

Any text message reply is converted to an email by the SMS Gateway and then sent back to the original sending email address, with the following format:

• From: The message is sent from <+country-code-phone-number>sms.textapp.net
• To: The message is sent to the email address of the original sender
• Subject: New SMS reply message
• Body: The body contains the following fields:
  1. Sender: the full international phone number of the sending phone
  2. Date: the date that the message was received
  3. Application Ref: an internally used, SMS Gateway message tracking code
  4. Time: the time that the message was received
  5. Body: the content of the message
  6. Original message: the content of the original message

If the reply is received in to a working email inbox, the email message can be replied to with the message sent to the SMS Gateway as an email, and then relayed to the recipient as an SMS.