SIPgate provides cloud‑based VoIP services with pay‑as‑you‑go pricing. Looking for free‑tier alternatives? Below are 20 free VoIP software solutions that offer calling, messaging, or PBX capabilities at no cost.
Get targeted exposure with custom position pinning and highlighted placement.
Free US‑based phone number with unlimited domestic calls, voicemail transcription, and integration with Google Workspace.
Ad‑supported free phone number for unlimited US/Canada calls and texts via its mobile and desktop apps.
Open‑source SIP softphone for Windows, macOS, Linux, iOS, and Android with audio/video calls and encryption.
Cross‑platform SIP/VoIP softphone offering basic calling features without a paid license.
Free, open‑source video‑conferencing platform that also supports high‑quality VoIP audio calls without registration.
Free version of the 3CX PBX for up to 16 simultaneous calls, includes web‑based softphone and mobile apps.
Open‑source GUI for Asterisk PBX, enabling free SIP trunking, call routing, and voicemail on your own server.
Industry‑standard open‑source telephony engine; you can build a completely free VoIP system on your own hardware.
Free, multi‑tenant PBX built on FreeSWITCH, offering SIP trunking, call routing, and web‑based management.
Open‑source SIP server for building scalable VoIP platforms; free to download and self‑host.
High‑performance open‑source SIP proxy/router, ideal for large‑scale free VoIP deployments.
Android SIP client that lets you register with any SIP provider and make free VoIP calls over Wi‑Fi or data.
Free messaging app with unlimited VoIP calls to other Viber users and low‑cost calls to regular phones.
Popular messaging platform offering free voice (and video) calls between WhatsApp accounts worldwide.
Privacy‑focused messenger that provides encrypted free voice and video calls between Signal users.
Free community platform with high‑quality voice channels for group calls and screen sharing.
Messaging app that includes free VoIP calls to other Telegram users with end‑to‑end encryption.
Free tier of Teams offering unlimited chat, audio calls, and up to 60 minute meetings for up to 100 participants.
Free Zoom account includes unlimited 1‑on‑1 audio/video meetings and group meetings up to 40 minutes.
Free developer tier with up to 2 SIP extensions, inbound/outbound calling via SIP trunk, and web‑based softphone.