[This API is no longer available and this page is being maintained purely for historical and research purposes.]
From their site: LignUp Communications Web Services enable developers with no CTI or SIP experience to easily integrate real-time communications into applications, portals and processes. LignUp powered Solutions connect any two phones independent of the existing telecom infrastructure. Welcome to our BETA developer program. Register to access some of our call control and media control web services, leveraging the Level 3 Network. Upon registration, you will receive 800 free, one-minute (maximum time limited) calls.