FreeSWITCH vs Kamailio
A side-by-side comparison of two self-hosted chat & communication options — licensing, setup difficulty, resource needs, and what each one replaces.
| Feature | FreeSWITCH | Kamailio |
|---|---|---|
| Deploy effort | Under-an-hour setup | Under-an-hour setup |
| Health score | 90 · Excellent | 87 · Excellent |
| Category | Chat & Communication | Chat & Communication |
| License | MPL-2.0 | GPL-2.0 |
| Language | C | C |
| Setup difficulty | Hard | Hard |
| Min. RAM | 512 MB | 256 MB |
| Deployment | docker, bare-metal, source | docker, bare-metal, source |
| GitHub stars | ★ 5,180 | ★ 2,952 |
| First released | 2006 | 2008 |
| Replaces | Twilio, Asterisk | Twilio |
What are FreeSWITCH and Kamailio?
FreeSWITCH
FreeSWITCH is a free communications software platform for building voice, video, and chat applications. It functions as a softswitch, PBX, and media gateway with extensive protocol support.
- Softswitch and PBX
- Voice, video, and chat
- Scriptable call control
- Wide codec and protocol support
Kamailio
Kamailio is a mature open-source SIP server capable of handling thousands of call setups per second. It is used to build VoIP, presence, instant messaging, and real-time communication services.
- High-throughput SIP routing
- Presence and IM support
- Extensive module library
- Carrier-grade scalability
FreeSWITCH vs Kamailio: key differences
Both projects are written in C. Licensing differs — MPL-2.0 for FreeSWITCH versus GPL-2.0 for Kamailio. Kamailio is the lighter option, starting around 256 MB of RAM against 512 MB for FreeSWITCH. FreeSWITCH is the more established project (first released 2006), while Kamailio arrived in 2008.
Why pick each one
Choose FreeSWITCH if…
- Released under the MPL-2.0 license
- First-class Docker support for quick deployment
- Mature project with 5.2k GitHub stars
- Written in C
Choose Kamailio if…
- Released under the GPL-2.0 license
- First-class Docker support for quick deployment
- Active community (3k GitHub stars)
- Written in C
Frequently asked questions
Is FreeSWITCH or Kamailio better?
Neither is universally better. FreeSWITCH has the larger community; both share a hard setup difficulty, so the decision comes down to features and licensing.
Are FreeSWITCH and Kamailio free and open-source?
Yes. FreeSWITCH is licensed under MPL-2.0 and Kamailio under GPL-2.0. Both can be self-hosted at no software cost.
Can I run FreeSWITCH and Kamailio with Docker?
FreeSWITCH: yes. Kamailio: yes.
Which is lighter on resources, FreeSWITCH or Kamailio?
Kamailio has the smaller minimum footprint at 256 MB of RAM, compared to about 512 MB for FreeSWITCH. Real-world usage depends on library size, user count, and enabled features.