Curated list of the top 30 free (or freemium) VoIP platforms that small businesses can use for voice calling, video conferencing, and unified communications without upfront licensing costs.
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On‑premise PBX with a web‑based console, support for up to 8 concurrent calls, mobile apps, and CRM integration.
Open‑source telephony engine that lets you build a custom PBX, IVR, and call‑center solution.
Graphical front‑end for Asterisk, offering drag‑and‑drop configuration of extensions, voicemail, and call routing.
Multi‑tenant, open‑source PBX built on FreeSWITCH; includes web UI, call queues, and SIP trunking.
All‑in‑one communications suite (now based on 3CX) that bundles PBX, email, chat, and fax.
Free SIP softphone for desktop and mobile with HD audio, video calls, and end‑to‑end encryption.
Self‑hosted, open‑source video‑conferencing platform that also supports SIP dial‑in/out for voice calls.
Cross‑platform SIP softphone with call recording, presence, and TLS/SRTP security.
German‑based SIP provider offering a free personal number with inbound/outbound calling to the EU.
Free U.S. phone number with voicemail, call forwarding, and integration with Google Workspace.
Skype‑to‑Skype voice and video calls are free; useful for internal communication and small‑team meetings.
Free tier includes unlimited chat, video meetings, and limited voice calling (audio‑only) for up to 300 users.
Community‑focused voice chat with server‑wide voice channels; can be repurposed for small‑business collaboration.
Free business account with Viber‑to‑Viber calls, chat, and basic chatbot integration.
Limited free tier that provides a single user number, unlimited internal calls, and mobile apps.
All‑in‑one suite with free cloud PBX, up to 12 users, call routing, and CRM integration.
Free tier for up to 10 agents, includes inbound/outbound calling, call masking, and basic analytics.
Free plan for up to 2 users with unlimited internal calls and limited PSTN minutes.
Team chat app with built‑in voice calls for up to 100 users; integrates with Zoho suite.
Self‑hosted video/voice chat app that works with any Nextcloud installation; supports SIP integration.
Open‑source team communication platform with optional voice call plugin and WebRTC support.
Open‑source Slack alternative; voice calling available via the built‑in Calls plugin.
Low‑latency, open‑source voice chat server often used by gaming teams but suitable for small business meetings.
End‑to‑end encrypted voice (and video) calls; free on mobile and desktop, ideal for privacy‑focused teams.
Secure, free voice calls between Telegram users; can be used for informal business conversations.
Free voice calls between WhatsApp Business accounts; integrates with catalog and quick replies.
Open‑source telephony framework that can act as a PBX, VoIP gateway, or softswitch.
Robust open‑source SIP proxy with advanced routing, load‑balancing, and NAT traversal features.