Get a PostShipping account from https://account.postshipping.com/ and start with 60 carriers!
See here if you are an existing Frontier Force user: How to sign up if you are an existing Frontier Force user
What is PostShipping?
PostShipping is a multi-carrier shipping API solution that allows integration with a diverse selection of global transport providers from a single REST API.
PostShipping supporting rates calculations, generate labels, and get tracking information from different carriers as long as you are the carrier’s account holders.
Checkout product page from http://postshipping.com