What is Kamailio used for?

Kamailio is an open-source SIP signaling server built for large VoIP and real-time communication platforms, with a focus on scalability and security. It is a good fit for carrier and operator VoIP platforms, load balancing and routing SIP traffic, and enterprise telephony infrastructure.

Is Kamailio open source?

Yes. Kamailio is open source under a custom licence. Its source code is on GitHub at kamailio/kamailio and is written mainly in C.

Yes. Kamailio is open source, so the software itself is free to use under the terms of its own licence.

Can I self-host Kamailio?

Yes. Kamailio can be self-hosted on your own server or infrastructure.

What are some alternatives to Kamailio?

Similar open-source tools in the Networking & VPN category include frp, Caddy and Pi-hole. SaaS products in the same category include Akamai, Amazon CloudFront and Amazon Route 53.

Is Kamailio actively maintained?

Yes. The most recent commit to Kamailio was on 2 October 2026, and the latest release is 6.0.8, published on 16 September 2026. The project has 3k stars on GitHub.

Kamailio: open-source networking & VPN

About Kamailio

Kamailio is an open-source implementation of a SIP signaling server. SIP is an open IETF standard, specified in RFC 3261, used to set up voice and other real-time communication sessions. The server is written in C and is aimed at flexibility, security and scalability, with topics that include VoIP, WebRTC, VoLTE and telephony.

It is designed for large deployments, such as IP telephony operators and carriers with big subscriber bases or high call volumes. Enterprises and individuals can also use it to provide VoIP, instant messaging and presence. The project is known for its flexibility, robustness and extensive module list, which the website describes in more detail.

The project began in 2001 at the Fraunhofer Fokus research institute in Berlin as SIP Express Router. A fork called OpenSER appeared in 2005 and was renamed Kamailio in 2008, after which the two projects merged. Fokus is no longer actively involved, and a worldwide community now develops the server, with events such as developer meetings and the Kamailio World Conference.

Key features

SIP signaling server
Scales to large subscriber bases and call volumes
VoIP, instant messaging and presence
WebRTC and VoLTE related support
Extensible module architecture

Good fit for

→Carrier and operator VoIP platforms
→Load balancing and routing SIP traffic
→Enterprise telephony infrastructure

Built with: C
Tags: sip; voip; telephony; webrtc; volte; sip-server; real-time-communication; self-hosted

Kamailio: questions and answers

What is Kamailio used for?: Kamailio is an open-source SIP signaling server built for large VoIP and real-time communication platforms, with a focus on scalability and security. It is a good fit for carrier and operator VoIP platforms, load balancing and routing SIP traffic, and enterprise telephony infrastructure.
Is Kamailio open source?: Yes. Kamailio is open source under a custom licence. Its source code is on GitHub at kamailio/kamailio and is written mainly in C.
Is Kamailio free?: Yes. Kamailio is open source, so the software itself is free to use under the terms of its own licence.
Can I self-host Kamailio?: Yes. Kamailio can be self-hosted on your own server or infrastructure.
What are some alternatives to Kamailio?: Similar open-source tools in the Networking & VPN category include frp, Caddy and Pi-hole. SaaS products in the same category include Akamai, Amazon CloudFront and Amazon Route 53.
Is Kamailio actively maintained?: Yes. The most recent commit to Kamailio was on 2 October 2026, and the latest release is 6.0.8, published on 16 September 2026. The project has 3k stars on GitHub.