Our products and services focus: voice and video over IP applications and communication systems.


Flexisip is a SIP proxy server implementation for IP to IP calls, compliant to RFC3261, written in C++11.

Flexisip includes specific features for mobile phones, like a push gateway to deliver SIP incoming calls or text messages on mobile platforms where receiving information while phone is off is unreliable or not supported (iOS, Android and Windows Phone 8).

Flexisip has the following main features:

Transports: SIP/UDP, SIP/TCP and SIP/TLS.
Nat aware with built-in media relay module and stun server.
Digest authentication based on external SQL password database or static file.
Routing based on registrar database or static route file, with forking.
Interconnected with push notifications systems for reliably notifying mobile apps of incoming calls or messages.
High level event logging for activity monitoring.
High availability and cluster mode operation for large deployments.


Affero GPLv3 or proprietary license.