Natterbox Alternatives

An open source telephony switching and private branch exchange service for Linux.

Open Source

The UCaaS Platform Built for MSPs​

VoIPstudio is an award-winning VoIP system that offers businesses of all sizes a scalable communication solution. It’s inexpensive, easy-to-use, offers a full suite of PBX features, and is fully integrated for CRM.

Try for free paid Free Trial $4.99 / Monthly (User)

FreeSWITCH is an open-source media application designed to support popular protools such as SIP and WebRTC and provides a platform to develop voice and video applications.

Social & Communications and Development

FusionPBX is an open source FreeSWITCH GUI.

Open Source

Kamailio® (successor of former OpenSER and SER) is an open source SIP server released under...

XiVO, première solution de téléphonie d'entreprise ToIP Open Source. TPE/PME Grande Entreprise / Centre de contact / Secteur Public. Contact: 04 37 49 78 10

VoipSwitch provides complete VoIP and unified communications solutions.

A SIP based implementation of a PBX / unified communications system.

sipXcom open source unified communications software is the standard for enterprise voice solutions. Voice, chat, IVR, presence and more in one application.

Open Source

Thirdlane Multi Tenant PBX provides a comprehensive and secure communication solution for businesses, MSPs and resellers. It offers a versatile platform with robust features and unparalleled value, all backed by Thirdlane's renowned reputation.

paid Free Trial

Ozeki Phone System XE is a Software PBX telephony platform for Windows.

Incredible PBX is a secure and feature-rich implementation of the Asterisk® PBX.