The sender field is the issuing of an SMS message. The sender is important because it identifies the originating entity and groups the different messages in the recipient's SMS Inbox.

The customization or change of sender is only available in some countries due to restriction and limitation of telephone operators.  

In the countries where the sender is limited, messages are delivered with a fixed or random sender that can be a short (shortcode) or long (longcode) number. This information can be consulted in the Services and credits by country section and also as a prior warning on the sending forms.

LabsMobile platform is prepared to choose a sender in each sending, both in the submission forms or WebSMS and via API with field sender. In the Account settings the list of senders used is found, the first value being the default sender.

The sender field has a maximum length of 11 characters and only allow standard letters and numbers ([a-zA-Z0-9]). In the case that the sender is numeric, the maximum length is 16 digits.