zap!

Mozilla-based scalable internet client communication

Zap is a cross-platform, open-source, Mozilla-based software project tasked with producing standards-based client software for advanced scalable internet communication.

We are implementing a stack of standards-based APIs covering areas such as DNS SRV and NAPTR resolution (RFC2782 and RFC2782), NAT traversal (RFC5389, draft-ietf-mmusic-ice-19), relaying (draft-ietf-behave-turn-11), path MTU discovery (draft-petithuguenin-behave-stun-pmtud-01), session invitation and control (SIP: RFC3261, RFC3262, RFC3263, RFC3265, RFC3327 and others), presence (RFC3856), session negotiation (RFC3264, SDP: RFC4566), real-time media playback and transport (RTP: RFC3550, RFC3551 and others) and support for various codecs such as G.711 and Speex.

The Zap APIs are implemented in a combination of C++ and JavaScript and abstracted using Mozilla's XPCOM/XPIDL technologies. XPCOM provides a robust framework for third party extensions, and, in combination with XPIDL ensures that the APIs are available both from C/C++ code and high-level scripting languages such as JavaScript.

Being based on the Mozilla codebase - the same technology that forms the basis of the Firefox and Thunderbird applications - means that we have a powerful cross-platform application framework at our disposal. Zap is packaged as a modified Mozilla XULRunner runtime, which can be used to create rich graphical client applications with a combination of cross-platform technologies such as XUL and JavaScript.

Zap ships with a reference XULRunner application, the Zap Universal SIP client, which showcases how the lower level APIs are accessed in a typical application setting. There is also the Zap Sandbox, which provides shell-like access to the Zap APIs.