From txtNation Wiki
txtNation make it easy for you to send USSD notifications to your users. Integrated directly into our popular txtNation Gateway API (HTTP), getting started couldn't be simpler:
- Contact txtNation to get USSD enabled on your account.
- Create a POST request just like normal MT SMS messages.
- Replace the network field with FLASHTXT.
- Hit the send button!
Within a few seconds the user will receive the message.
Differences to SMS
- USSD messages are up to 182 alphanumeric characters in length.
- USSD messages are not stored on the handset's long-term memory. Once the user has acknowledged the message it is removed.