This page selectively collected facts from the public domain showing where and how Kamailio® or SER are used world wide, from the start of SIP Express Router (SER) project back in 2001.

If you are using a VoIP service these days it is a very high chance that your calls are routed via instances of this open source SIP server. Started back in 2001, SER was the first open source SIP server, contributing to the development of SIP protocol and markets over the last 9 years. Kamailio (OpenSER) split from 2005 to 2008 boosted the number of features, contributing back an ecosystem with a very active user and developer community.

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Web references
World-wide use case samples
  • Used By Directory – list of products, solutions or services relying on Kamailio
  • 1&1 – one of the biggest VoIP services world wide, hosting over 3 000 000 subscribers and performing over 1.5 billions minutes routed per month. In 2009 they merged in the Freenet service, adding extra 0.8 million new subscribers
  • sipgate – one of the oldest VoIP providers, with hundred thousands of active subscribers, focusing on residential and SME markets in Germany, UK and Austria
  • truphone – MVNO focused on IP – GSM convergence. Their service enables smart phones  and gadgets to take advantage of VoIP technology, including but not limited to iPhone, iPod, Nokia, NexusOne, Motorola, …
  • telio – growing VoIP provider in Norway serving a large number of active subscribers (over 150 000 in 2008)
  • freenet – among VoIP pioneers in Germany, they delivered VoIP service to over 800 000 subscribers, integrated in 2009 into 1&1
  • voztelecom – Spanish telephony provider focused in Iberian and Latin America markets. Main target is SME and residential markets, offering as well hosted pbx services.
  • iptelorg/tekelec – Tekelec bought company in 2005, along with full SER usage license. Many of main developers of SIP Express Router (SER) continue to work at Tekelec to build in-house series of SIP products based on the popular SIP server.
  • – FhG Fokus prototype implementation of ITU IMS specifications, used as reference and testbed for next generation services development.
  • – free VoIP service from the developers of Ekiga softphone, offering lot of the edge features provided by Kamailio (OpenSER), like SIMPLE presence.
  • – free VoIP service from the developers of SER, termination to PSTN being possible by using own gateway
  • – free VoIP service from forum maintained together with Kamailio (OpenSER) developers, offering UK numbers and termination to PSTN by credit accumulated from incoming calls
  • XtraTelecom – Spanish telephony provider focused on enterprise market, offering SIP trunking services along with hosted PBX’s
  • (world wide network of academic institutes: MIT, INRIA and more)
  • DIDXchange – where over 19,000 IP and rich communications providers from 163 nations complete one interop to buy and/or sell SIP DID/DDI phone numbers among each other, saving time and money. A majority are using open source such Kamailio. Numbers from 57 countries are mutually available to all with a need for more, all wholesale.
  • SIP Outbound – SIP Outbound Proxy Service helps bypassing the blocking of VoIP port 5060. It acts as a transparent SIP Proxy on port 53, which allows VoIP users to bypass the restrictions imposed by their operators or ISPs.
Books, articles and blogs

If you want to list any interesting reference on this page, do not hesitate to contact us.