About me


Henning Westerholt is an experienced IT manager for IT Operations and software development. During his career he was responsible for different products at IT service providers and also for the internal IT of different large manufacturing companies in Germany. He provides consulting services for Kamailio and VoIP services in the performance, reliability and security areas. Henning is one of the core developers of the Kamailio Open Source project since 2007 and member of the Kamailio Management team.

Management experience

He has a broad experience as IT manager, having managed one or several teams in IT Operations and software development in different roles in last 10 years. Henning is especially experienced in the IT Operations area, where he was responsible for a department of over 50 people with a budget of app. 20 Million Euro at TRUMPF.

Voice over IP

He was some years ago responsible at 1&1 for the operation of their Voice over IP and DSL platform. This includes the maintenance and deploying of extensions of the Kamailio, Radius, ACS and order middle-ware systems of 1&1. Henning was in charge with one of the biggest VoIP deployments out there in 2008, using Kamailio (OpenSER) as core routing system: over 3 Million users, over 7 Million phone numbers and 1.5 Million routed minutes per month.

Open Source

Henning is a long term Linux user and contributor to several Open Source projects, participating in world wide events, presenting about Kamailio (OpenSER) and open source. You can find his current presentations in his blog, old presentations are available here. If you like to support his Open Source work please visit Patreon.


He holds a bachelor and master degree in applied computer science from the University of Siegen.

More information

You can find more information about Henning Westerholt on different platforms:

Linkedin link Xing link Github link


You can reach Henning Westerholt at: mail at skalatan dot de