Linphone

Linphone is an open source softphone for VoIP, video calling and instant messaging, developed by Belledonne Communications. It occupies two positions at once: a free application anyone can use, and a set of software building blocks that companies license and build products on. Understanding which of those you are buying is the first thing to establish.

The application and service are free to use, supported by an FAQ and a community space. Underneath sits Liblinphone, the cross-platform library on which Linphone itself is built, offered to organisations that want to embed calling into their own products. The company describes a complete software suite for enterprise communications covering IP telephony, instant messaging and video conferencing, and a full solution comprising SDK, server and applications for building your own communication products from its components.

Commercial services extend well beyond licensing the code. Belledonne will customise Linphone to a customer's brand and business requirements, which supports white-label deployment. It will handle server installation to optimise a deployment rather than leaving the operator to do it. Annual maintenance contracts are offered to guarantee the longevity of a communication solution built on the stack, and bespoke feature development is quoted on request.

The intended customers are therefore of three kinds: developers integrating calling features into existing products, organisations building a custom or white-label softphone, and enterprises and call centres wanting a turnkey unified communications solution. Individual users sit outside that commercial structure and use the free application. Pricing for the commercial offerings is quoted per engagement rather than published.