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Use SIP trunks, WebRTC & Apps

Slash your Phone Bill by 80%

Your SIP Server Software. Free with 3CX.

Get your free SIP Server Software available on Windows, Linux or in the cloud.

Looking to set up a complete IP PBX in minutes? Then look no further. 3CX is a SIP server that works with popular VoIP Gateways and SIP phones and allows you to do just that. You can download and install 3CX’s SIP software on Windows or Linux in a matter of minutes. And once installed the configuration can be done easily via the easy to use web interface. With softphones for Windows, Mac, iOS and Android included, users have access to a full suite of Unified Communications features.

  • Free for 16 sim calls – unlimited extensions

  • Free web conferencing (25 participants)

  • Supports SIP 2.0

  • Supports standard PSTN/Telephone lines via SIP Gateways and Audiocodes

  • Supports the use of SIP Trunks and SIP providers

  • Supports main codecs including G711, GSM, IspeeX and ILBLC

  • Open-platform – works with most popular SIP devices
Install 3CX's SIP server software on-premise or in the cloud

Free for up to 1 year! Select preferred deployment:


for Linux on a $200 appliance or as a VM

Get the ISO


for Windows as a VM

Download the setup file

On the cloud

In your Google, Amazon, Azure account

Take the PBX Express