VoIP SIP Server SDK provides a powerful and highly customizable API solution based on the Session Initiation Protocol (SIP) to quickly add SIP based server features to your application or to build new one from scratch. It accelerates the development of Session Initiation Protocol compliant server (registrar) with a fully-customizable user interface and brand name.
Our product is based on IETF standards (Session Initiation Protocol, STUN, etc.), so it should be compatible with other standard based products such as Asterisk, OpenSER other.

The software has the following features:

# Registrar
# Highly customizable
# SIP client authentication
# PC to PC call services.
# VPN support
# Royalty free licensing
# No yearly/monthly fee