We just fixed the bug that was causing the callerid parameter to not be properly passed to the SMS network via our SMS API. Note: only our numbers are able to appear in the caller id of text messages sent via our service. Here’s an example: http://www.teleku.com/sms/4805551212/This+is+new+test?callerid=2532181084&apikey=123abc Thanks for your patience and happy SMSing!