CDRTool is an Open Source solution that provides mediation, accounting and tracing for Call Detail Records enerated by OpenSIPS by using RADIUS protocol and OpenSIPS siptrace facility.
These are SIP and WebRTC end-points based on Open Standards that we have developed since 2005, for various desktop and mobile operating systems.
SIP allows the endpoints to negotiate and combine any type of session they mutually understand like Audio, Video, Instant Messaging (IM), File Transfer, Desktop Sharing and provides a generic event notification system with real-time Publications and Subscriptions about state changes that can be used for asynchronous services like Presence, Message Waiting Indicator and Busy Line Appearance.
We are pioneers of end-to-end encryption for all media: zRTP (audio and video), OTR and PGP (messaging and file transfers).
MediaProxy is a media relay for RTP/RTCP and UDP streams that works in tandem with OpenSIPs to provide NAT traversal capability for media streams from SIP user agents located behind NAT.
SIP SIMPLE Client SDK version 5.4.0 has been released.
This version delivers interoperability with audio and video WebRTC end-points, and zRTP key negotiation with Sylk Suite.
Full release notes and discussion are available in the announcement on the SIP Beyond VoIP mailing list: May 2026 announcement.
Sylk Suite is a set of applications that act both as infrastructure and end-points to provide advanced real-time media services that mirror functionality available from commercial vendors (WhatsApp and Telegram). The differentiation is in the use of open standards and the availability of source code.
Sylk Suite is open-source software available in binary format and as source code. Using Sylk Suite you can build your own real-time communications infrastructure on the operating system of your choice and under your own Internet domain for web, mobile and desktop clients.
Platform components:
SIP/WebRTC application server
Mobile push notifications server
Desktop client for Windows, Linux and MacOS
Web page compatible with WebRTC enabled browsers
Client development SDK
The platform supports one-to-one audio/video and multiparty audio/video, screen-sharing, file transfers and text chat media, with end-to-end encryption for all media.
The application server is SIP compliant and requires a SIP server to operate. The client application is written in JavaScript, using React Native for mobile and Electron for desktop. The backend application server is written in Python. The push notifications server is compatible with Apple and Google (Firebase).
The platform is horizontally scalable using SIP Thor.
The server supports SIP and XMPP signaling, mobile push notifications, end-to-end encrypted text messaging with offline storage, RTP, MSRP and WebRTC media planes, has built-in capabilities for creating multiparty conferences with wideband Audio, IM and File Transfers, and can be easily extended with other custom applications using the Python language.
For purchasing inquiries go to Purchasing page.
Full documentation and source code at sylkserver.com.
AG Projects has rolled out zRTP end-to-end encryption across its Sylk Suite stack. The implementation is cross-platform and supported by the SIP SIMPLE client SDK, the Blink SIP client, and the Sylk Mobile and Web clients.
On WebRTC clients (mobile and browser) the implementation relies on the Insertable Streams technique. Insertable Streams expose encoded media frames to JavaScript before they hit the network, allowing zRTP-derived keys to be applied end-to-end on top of the hop-by-hop SRTP that the WebRTC stack already provides — so audio and video stay encrypted all the way between peers, even when traffic traverses SylkServer or a TURN relay.
Implementation details, key-exchange flow and verification UX are documented in the Sylk Mobile repository: github.com/AGProjects/sylk-mobile/tree/master/docs/encryption.
SIP Clients and Beyond, a presentation about status of open source SIP clients available in the public domain.. or all about SDP sinners and the ultimate answer for the question why so many Romanians are involved in the VoIP industry.
AG Projects provides now standard with its SIP Thor platform integration with MS Teams.
For more information see:
https://docs-new.sipthor.net/book/general-sip-platform/article/routes_msteams/
We are welcoming into our team one developer with Python and C experience that will be involved with the development and maintance of multimedia real-time communications solutions based on SIP/WebRTC protocols. Proven experience with management of open source projects is required.
Keywords: Python, Cython, C, Debian, Linux