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FreeSWITCH vs Kamailio: catalog facts
FreeSWITCH	Kamailio
Free Free source code; commercially supported builds and professional services are available.	Free Free and open source under the GPLv2 or later.
Windows, macOS, Linux, Self-hosted	Linux, Self-hosted
Runs on hardware from a Raspberry Pi to multi-core servers Handles voice, video and chat	Handles thousands of call setups per second WebSocket support for WebRTC plus TLS for secure signalling
Distributed mainly as source code to build Requires telephony and server administration knowledge	Infrastructure for engineers, not an end-user calling app Configuration requires solid SIP and VoIP knowledge
Self-hosted	Downloadable app, Self-hosted
Open source	Open source
License not stated	License: GPL-2.0-or-later
No account needed	No account needed
Not stated if it works offline	Not stated if it works offline
Official website Full listing and sources Checked September 24, 2026	Official website Full listing and sources Checked October 2, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.