Yes. It is possible to set your own sender id. Please be aware that this option is not supported to all operators. The sender ID has a maximum length of 14 digits or 11 characters. Attention! Only the following characters are possible: A to Z, a to z and 0 to 9. No spaces or any other symbols and characters are possible.
When you compose your message in the web interface you are asked to select or create your own sender id. When sending to certain countries (e.g. Belgium) you are obliged to select a shortcode because it is not possible to deliver using an alphanumerical sender id. Please see below for a preliminary overview.