3CX offers a feature‑rich PBX with call handling, video conferencing, and chat. Below is a curated list of 20 free‑of‑charge VoIP platforms and soft‑phones that can serve as viable replacements for 3CX (Free Edition).
Get targeted exposure with custom position pinning and highlighted placement.
Open‑source telephony engine that powers PBX, VoIP gateways, and conference servers; highly extensible via dialplan scripting.
Web‑based GUI for Asterisk that simplifies PBX configuration, voicemail, IVR, and call routing.
Multi‑tenant PBX built on FreeSWITCH, offering call routing, voicemail, fax, and a modern HTML5 UI.
High‑performance SIP server designed for large‑scale deployments, handling registration, routing, and load‑balancing.
Robust SIP proxy and registrar with advanced routing, NAT traversal, and real‑time analytics.
Community‑driven fork of Elastix that combines Asterisk PBX, CRM, and call‑center features.
Open‑source unified communications platform offering PBX, video, chat, and API‑first integration.
Scalable telephony platform for building soft‑switches, conference bridges, and media gateways.
Cross‑platform SIP soft‑phone with audio/video calls, instant messaging, and end‑to‑end encryption.
Open‑source video‑conferencing solution that also supports SIP audio calls without needing an account.
Free SIP/IMS soft‑phone for Windows, macOS, Linux, iOS, and Android with HD audio and video support.
Enterprise‑grade SIP communications suite offering PBX, voicemail, and unified messaging.
Open‑source call‑center solution built on Asterisk, providing inbound/outbound dialing, predictive dialing, and agent tools.
Free SIP service that supplies SIP credentials, inbound numbers, and basic call handling for testing or small deployments.
Free soft‑phone for Android and iOS that supports SIP, video calls, and push notifications.
Lightweight Windows SIP client focused on high‑quality audio and simple configuration.
Modular telephony engine that can act as a PBX, gateway, or media server with scripting support.
Free version of the PBXware suite offering core PBX features, voicemail, and basic call routing.
Integrated VoIP module within the Odoo ERP suite, enabling click‑to‑call, call logging, and CRM linking.
Decentralized, peer‑to‑peer communication app supporting secure audio/video calls without a central server.