Following is a custom function I built to send SMS messages out of filemaker using textgrid which is about half the price of Twilio.
parameters are CellNumber and Message
the account SID, Authorization Token and the number you purchased from textGrid are available to you after signing up with them. As far as I know this works in the United states but Im sure can be modified to work overseas. I tried to post this to briandunning custom functions but was unable to create an account there to do so.
Use the insert URL to $$response
"httpspost://" & "your account sid" & ":" & "authorization token" & "@api.textgrid.com/2010-04-01/Accounts/" & "your account sid" & "/Messages.json?To=+1" &Filter(CellNumber;"0123456789") & "&From=+1" & "the number you purchased from textGrid" & "&Body=" &Message