Compare software

Flexisip vs OpenSIPS: catalog facts
Flexisip	OpenSIPS
Best for: Running your own SIP VoIP service, especially for Linphone mobile users	Best for: VoIP engineers and providers building SIP infrastructure
Free Free under the AGPL 3.0, with a paid proprietary licence for closed-source use.	Free Free and open source; paid training courses are offered separately.
Self-hosted	Linux, Self-hosted
Push gateway delivers calls and messages to mobile apps in the background Proxy, presence and B2BUA in one suite All 4 strengths for Flexisip Push gateway delivers calls and messages to mobile apps in the background Proxy, presence and B2BUA in one suite Powers the public linphone.org SIP service Can run on embedded hardware	Handles high SIP traffic volumes Covers many roles from PBX to load balancer All 4 strengths for OpenSIPS Handles high SIP traffic volumes Covers many roles from PBX to load balancer Active development with a 4.0 release in 2026 Documentation with working config samples
Requires SIP and VoIP knowledge to deploy Conference server is now a separate package	Steep learning curve, aimed at telecom engineers Signaling server only, not an end-user calling app
Self-hosted	Downloadable app, Self-hosted
Open source	Open source
License: AGPL-3.0	License: GPL-2.0
Not stated if an account is needed	No account needed
Not stated if it works offline	Not stated if it works offline
Official website Full listing and sources Sources for Flexisip linphone.org/en/flexisip-sip-server github.com/BelledonneCommunications/flexisip Catalog checked October 2, 2026	Official website Full listing and sources Sources for OpenSIPS opensips.org Catalog checked October 2, 2026

“Not stated” means we have not confirmed it. Features can vary by device and plan.