One embodiment of the present invention provides a system that facilitates developing applications with telephony functionality. The system includes a session initiation protocol (SIP) gateway configured to interface with a public switched telephone network (PSTN). The SIP gateway translates telephone calls from telephones coupled to the PSTN to SIP protocol messages. A SIP server coupled to the SIP gateway accepts these SIP protocol messages and an application server accesses a voice extensible markup language (VXML) page on behalf of the SIP server. A VXML gateway provides access to the VXML page by a users of the telephones.