Flexisip Server

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Flexisip is a complete and scalable SIP server suite that includes several modules: a proxy, a presence server, a conference server, a back-to-back user agent, and Flexisip account manager for the creation and administration of SIP accounts.

Flexisip is an easy-to-install SIP server solution, offering all the features required to deploy your own SIP service tuned for mobile or desktop applications, « out of the box ».

The free sip.linphone.org SIP service has run on Flexisip since 2011, and enables Linphone users to create their own SIP addresses to connect with each other.

Proxy :

  • NAT-aware with built-in media relay module and ICE/STUN support
  • interconnected with Apple's and Google's push notification systems
  • high availability and cluster mode for large deployments
  • high-level event logging for activity monitoring
  • digest and TLS client certificate authentication

Presence :

Flexisip manages SIP SUBSCRIBE and PUBLISH from client applications, in order to :

  • identify users of the service within the address book
  • provide users with real-time presence status 

Conference (for group chat and group calls):

  • entirely SIP-based solution
  • efficient management of groups and participants
  • multi-device support
  • notification of group events (users joining or leaving, new admins etc.)


  • media encryption transcoding
  • media codec transcoding
  • SIP bridge, for interconnection with PSTN gateways


Flexisip account manager:

  • SIP account creation and management, by end-users or admins
  • remote provisioning of Linphone-based apps (including app's settings, user account, contact list...)
  • web admin platform

Flexisip can be integrated into your SIP infrastructure for various purposes, for example IN THE CLOUD in order to run your own VoIP service,  EMBEDDED in small hardware systems or in its PUSH GATEWAY mode of operation.

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